Computer Science & Mathematics
http://www.mdpi.com/journal/computer-math
Latest open access articles published in Computer Science & Mathematics at http://www.mdpi.com/journal/computer-math<![CDATA[Information, Vol. 8, Pages 12: The Matrix Method of Representation, Analysis and Classification of Long Genetic Sequences]]>
http://www.mdpi.com/2078-2489/8/1/12
The article is devoted to a matrix method of comparative analysis of long nucleotide sequences by means of presenting each sequence in the form of three digital binary sequences. This method uses a set of symmetries of biochemical attributes of nucleotides. It also uses the possibility of presentation of every whole set of N-mers as one of the members of a Kronecker family of genetic matrices. With this method, a long nucleotide sequence can be visually represented as an individual fractal-like mosaic or another regular mosaic of binary type. In contrast to natural nucleotide sequences, artificial random sequences give non-regular patterns. Examples of binary mosaics of long nucleotide sequences are shown, including cases of human chromosomes and penicillins. The obtained results are then discussed.Information2017-01-1781Article10.3390/info8010012122078-24892017-01-17doi: 10.3390/info8010012Ivan StepanyanSergey Petoukhov<![CDATA[IJGI, Vol. 6, Pages 20: SSIEGNOS: A New Asian Single Site Tropospheric Correction Model]]>
http://www.mdpi.com/2220-9964/6/1/20
This paper proposes a new Asian single site tropospheric correction model called the Single Site Improved European Geostationary Navigation Overlay Service model (SSIEGNOS) by refining the European Geostationary Navigation Overlay Service (EGNOS) model at a single site. The performance of the SSIEGNOS model is analyzed. The results show that (1) the bias and root mean square (RMS) error of zenith tropospheric delay (ZTD) calculated from the EGNOS model are 0.12 cm and 5.87 cm, respectively; whereas those of the SSIEGNOS model are 0 cm and 2.52 cm, respectively. (2) The bias and RMS error show seasonal variation in the EGNOS model; however, little seasonal variation is observed in the SSIEGNOS model. (3) The RMS error decreases with increasing altitude or latitude in the two models; however, no such relationships were found in the bias. In addition, the annual predicted bias and RMS error in Asia are −0.08 cm and 3.14 cm for the SSIEGNOS model, respectively; however, the EGNOS and UNB3m (University of New Brunswick) models show comparable predicted results. Relative to the EGNOS model, the annual predicted bias and RMS error decreased by 55% and 48%, respectively, for the SSIEGNOS model.ISPRS International Journal of Geo-Information2017-01-1761Article10.3390/ijgi6010020202220-99642017-01-17doi: 10.3390/ijgi6010020Liangke HuangShaofeng XieLilong LiuJunyu LiJun ChenChuanli Kang<![CDATA[J. Imaging, Vol. 3, Pages 5: LaFiDa—A Laserscanner Multi-Fisheye Camera Dataset]]>
http://www.mdpi.com/2313-433X/3/1/5
In this article, the Laserscanner Multi-Fisheye Camera Dataset (LaFiDa) for applying benchmarks is presented. A head-mounted multi-fisheye camera system combined with a mobile laserscanner was utilized to capture the benchmark datasets. Besides this, accurate six degrees of freedom (6 DoF) ground truth poses were obtained from a motion capture system with a sampling rate of 360 Hz. Multiple sequences were recorded in an indoor and outdoor environment, comprising different motion characteristics, lighting conditions, and scene dynamics. The provided sequences consist of images from three—by hardware trigger—fully synchronized fisheye cameras combined with a mobile laserscanner on the same platform. In total, six trajectories are provided. Each trajectory also comprises intrinsic and extrinsic calibration parameters and related measurements for all sensors. Furthermore, we generalize the most common toolbox for an extrinsic laserscanner to camera calibration to work with arbitrary central cameras, such as omnidirectional or fisheye projections. The benchmark dataset is available online released under the Creative Commons Attributions Licence (CC-BY 4.0), and it contains raw sensor data and specifications like timestamps, calibration, and evaluation scripts. The provided dataset can be used for multi-fisheye camera and/or laserscanner simultaneous localization and mapping (SLAM).Journal of Imaging2017-01-1731Article10.3390/jimaging301000552313-433X2017-01-17doi: 10.3390/jimaging3010005Steffen UrbanBoris Jutzi<![CDATA[Information, Vol. 8, Pages 11: Four-Switch Three-Phase PMSM Converter with Output Voltage Balance and DC-Link Voltage Offset Suppression]]>
http://www.mdpi.com/2078-2489/8/1/11
High power quality, efficiency, complexity, size, cost effectiveness and switching losses of the direct current to alternating current (DC–AC) conversion system are crucial aspects in industrial applications. Therefore, the four-switch three-phase inverter (4S3P) has been proposed as an innovative inverter design. However, this topology has been known to have many performance limitations in the low-frequency region, because of the generation of an unbalanced voltage leading to an unbalanced current due to the fluctuation and offset of the centre tap voltage of the DC-link capacitors. Those drawbacks are investigated and solved in this paper in order to provide pure sinusoidal output voltages. The generated output voltages are controlled using proportional-integral (PI) controllers to follow the desired voltages. Furthermore, the DC-link capacitor voltage offset is mitigated by subtracting the direct component from the control reference voltage using low pass filters, where this direct voltage component provides the direct current component which leads to DC-link capacitor voltage divergence. A simulation model and experimental setup are used to validate the proposed concept. Many simulation and experimental results are carried out to show the effectiveness of the proposed control scheme.Information2017-01-1781Article10.3390/info8010011112078-24892017-01-17doi: 10.3390/info8010011Fadil HichamDriss YousfiElhafyani Mohamed LarbiAite Youness<![CDATA[IJGI, Vol. 6, Pages 19: A Graph-Based Min-# and Error-Optimal Trajectory Simplification Algorithm and Its Extension towards Online Services]]>
http://www.mdpi.com/2220-9964/6/1/19
Trajectory simplification has become a research hotspot since it plays a significant role in the data preprocessing, storage, and visualization of many offline and online applications, such as online maps, mobile health applications, and location-based services. Traditional heuristic-based algorithms utilize greedy strategy to reduce time cost, leading to high approximation error. An Optimal Trajectory Simplification Algorithm based on Graph Model (OPTTS) is proposed to obtain the optimal solution in this paper. Both min-# and min-ε problems are solved by the construction and regeneration of the breadth-first spanning tree and the shortest path search based on the directed acyclic graph (DAG). Although the proposed OPTTS algorithm can get optimal simplification results, it is difficult to apply in real-time services due to its high time cost. Thus, a new Online Trajectory Simplification Algorithm based on Directed Acyclic Graph (OLTS) is proposed to deal with trajectory stream. The algorithm dynamically constructs the breadth-first spanning tree, followed by real-time minimizing approximation error and real-time output. Experimental results show that OPTTS reduces the global approximation error by 82% compared to classical heuristic methods, while OLTS reduces the error by 77% and is 32% faster than the traditional online algorithm. Both OPTTS and OLTS have leading superiority and stable performance on different datasets.ISPRS International Journal of Geo-Information2017-01-1661Article10.3390/ijgi6010019192220-99642017-01-16doi: 10.3390/ijgi6010019Fan WuKun FuYang WangZhibin Xiao<![CDATA[Algorithms, Vol. 10, Pages 15: Toward Personalized Vibrotactile Support When Learning Motor Skills]]>
http://www.mdpi.com/1999-4893/10/1/15
Personal tracking technologies allow sensing of the physical activity carried out by people. Data flows collected with these sensors are calling for big data techniques to support data collection, integration and analysis, aimed to provide personalized support when learning motor skills through varied multisensorial feedback. In particular, this paper focuses on vibrotactile feedback as it can take advantage of the haptic sense when supporting the physical interaction to be learnt. Despite each user having different needs, when providing this vibrotactile support, personalization issues are hardly taken into account, but the same response is delivered to each and every user of the system. The challenge here is how to design vibrotactile user interfaces for adaptive learning of motor skills. TORMES methodology is proposed to facilitate the elicitation of this personalized support. The resulting systems are expected to dynamically adapt to each individual user’s needs by monitoring, comparing and, when appropriate, correcting in a personalized way how the user should move when practicing a predefined movement, for instance, when performing a sport technique or playing a musical instrument.Algorithms2017-01-16101Article10.3390/a10010015151999-48932017-01-16doi: 10.3390/a10010015Olga Santos<![CDATA[IJGI, Vol. 6, Pages 18: An Improved Information Value Model Based on Gray Clustering for Landslide Susceptibility Mapping]]>
http://www.mdpi.com/2220-9964/6/1/18
Landslides, as geological hazards, cause significant casualties and economic losses. Therefore, it is necessary to identify areas prone to landslides for prevention work. This paper proposes an improved information value model based on gray clustering (IVM-GC) for landslide susceptibility mapping. This method uses the information value derived from an information value model to achieve susceptibility classification and weight determination of landslide predisposing factors and, hence, obtain the landslide susceptibility of each study unit based on the clustering analysis. Using a landslide inventory of Chongqing, China, which contains 8435 landslides, three landslide susceptibility maps were generated based on the common information value model (IVM), an information value model improved by an analytic hierarchy process (IVM-AHP) and our new improved model. Approximately 70% (5905) of the inventory landslides were used to generate the susceptibility maps, while the remaining 30% (2530) were used to validate the results. The training accuracies of the IVM, IVM-AHP and IVM-GC were 81.8%, 78.7% and 85.2%, respectively, and the prediction accuracies were 82.0%, 78.7% and 85.4%, respectively. The results demonstrate that all three methods perform well in evaluating landslide susceptibility. Among them, IVM-GC has the best performance.ISPRS International Journal of Geo-Information2017-01-1661Article10.3390/ijgi6010018182220-99642017-01-16doi: 10.3390/ijgi6010018Qianqian BaYumin ChenSusu DengQianjiao WuJiaxin YangJingyi Zhang<![CDATA[MCA, Vol. 22, Pages 4: Design Optimization of the Lines of the Bulbous Bow of a Hull Based on Parametric Modeling and Computational Fluid Dynamics Calculation]]>
http://www.mdpi.com/2297-8747/22/1/4
To reduce the ship wave-making resistance, the lines of the bulbous bow of a hull are optimized by an automatic optimization platform at the ship design stage. Parametric modeling was applied to the hull by using non-uniform rational basis spline (NURBS). The Rankine-source panel method was used to calculate the wave-making resistance. A hybrid optimization strategy was applied to achieve the optimization goal. A Ro-Ro ship was taken as an example to illustrate the optimization method adopted, with the objective to minimize the wave-making resistance. The optimization results show that wave-making resistance obviously reduces and the wave-shape of the near bow becomes gentle after the lines of the bulbous bow of the hull are optimized, which demonstrates the validity of the proposed optimization design strategy.Mathematical and Computational Applications2017-01-16221Article10.3390/mca2201000442297-87472017-01-16doi: 10.3390/mca22010004Weilin LuoLinqiang Lan<![CDATA[IJGI, Vol. 6, Pages 17: 3D Space Shift from CityGML LoD3-Based Multiple Building Elements to a 3D Volumetric Object]]>
http://www.mdpi.com/2220-9964/6/1/17
In contrast with photorealistic visualizations, urban landscape applications, and building information system (BIM), 3D volumetric presentations highlight specific calculations and applications of 3D building elements for 3D city planning and 3D cadastres. Knowing the precise volumetric quantities and the 3D boundary locations of 3D building spaces is a vital index which must remain constant during data processing because the values are related to space occupation, tenure, taxes, and valuation. To meet these requirements, this paper presents a five-step algorithm for performing a 3D building space shift. This algorithm is used to convert multiple building elements into a single 3D volumetric building object while maintaining the precise volume of the 3D space and without changing the 3D locations or displacing the building boundaries. As examples, this study used input data and building elements based on City Geography Markup Language (CityGML) LoD3 models. This paper presents a method for 3D urban space and 3D property management with the goal of constructing a 3D volumetric object for an integral building using CityGML objects, by fusing the geometries of various building elements. The resulting objects possess true 3D geometry that can be represented by solid geometry and saved to a CityGML file for effective use in 3D urban planning and 3D cadastres.ISPRS International Journal of Geo-Information2017-01-1561Article10.3390/ijgi6010017172220-99642017-01-15doi: 10.3390/ijgi6010017Shen YingRenzhong GuoJie YangBiao HeZhigang ZhaoFengzan Jin<![CDATA[MCA, Vol. 22, Pages 7: Spatiotemporal Dynamics of a Delayed and Diffusive Viral Infection Model with Logistic Growth]]>
http://www.mdpi.com/2297-8747/22/1/7
Viruses have important influences on human health: they not only cause some common diseases, but also cause serious illnesses. Moreover, the conventional medicines usually fail to prevent or treat them, and viral infections are hard to treat because viruses live inside the body’s cells. However, some mathematical models can help to understand the viral transmission mechanism and control viral diseases. In this paper, a delayed viral infection model with spatial diffusion and logistic growth is presented. The asymptotic stability of nonnegative uniform steady states is investigated by utilizing the linearized method and constructing the proper Lyapunov functional, respectively. The existence of Hopf bifurcation from the positive equilibrium point is established by analyzing the corresponding characteristic equation and the direction of bifurcation, and the properties of bifurcating periodic solutions are derived by the aid of the normal form theory for partial functional differential equations. Then, the cross-diffusion system is introduced. Furthermore, some numerical simulations are carried, out and discussions are given.Mathematical and Computational Applications2017-01-14221Article10.3390/mca2201000772297-87472017-01-14doi: 10.3390/mca22010007Kejun Zhuang<![CDATA[Mathematics, Vol. 5, Pages 6: Zoology of Atlas-Groups: Dessins D’enfants, Finite Geometries and Quantum Commutation]]>
http://www.mdpi.com/2227-7390/5/1/6
Every finite simple group P can be generated by two of its elements. Pairs of generators for P are available in the Atlas of finite group representations as (not necessarily minimal) permutation representations P . It is unusual, but significant to recognize that a P is a Grothendieck’s “dessin d’enfant” D and that a wealth of standard graphs and finite geometries G —such as near polygons and their generalizations—are stabilized by a D . In our paper, tripods P − D − G of rank larger than two, corresponding to simple groups, are organized into classes, e.g., symplectic, unitary, sporadic, etc. (as in the Atlas). An exhaustive search and characterization of non-trivial point-line configurations defined from small index representations of simple groups is performed, with the goal to recognize their quantum physical significance. All of the defined geometries G ′ s have a contextuality parameter close to its maximal value of one.Mathematics2017-01-1451Article10.3390/math501000662227-73902017-01-14doi: 10.3390/math5010006Michel PlanatHishamuddin Zainuddin<![CDATA[Algorithms, Vol. 10, Pages 13: A Fault Detection and Data Reconciliation Algorithm in Technical Processes with the Help of Haar Wavelets Packets]]>
http://www.mdpi.com/1999-4893/10/1/13
This article is focused on the detection of errors using an approach that is signal based. The proposed algorithm considers several criteria: soft, hard and very hard recognition error. After the recognition of the error, the error is replaced. In this sense, different strategies for data reconciliation are associated with the proposed criteria error detection. Algorithms in several industrial software platforms are used for detecting errors of sensors. Computer simulations confirm the validation of the presented applications. Results with actual sensor measurements in industrial processes are presented.Algorithms2017-01-14101Article10.3390/a10010013131999-48932017-01-14doi: 10.3390/a10010013Paolo Mercorelli<![CDATA[Administrative Sciences, Vol. 7, Pages 3: Retailers’ Responsibility towards Consumers and Key Drivers of Their Development in Poland]]>
http://www.mdpi.com/2076-3387/7/1/3
Multinational retailers are now very powerful and their activities could influence whole economies. In this paper, we investigate why they engage in corporate social responsibility (CSR) practices towards consumers, how it fosters sustainable development, and what the role of institutions are in the process of developing CSR strategies. Changes that have taken place in Poland since 1989, when the transition process into a market economy started, constituted an excellent research field due to the fact that the retail market was not saturated at the beginning, consumers were only slightly protected by the law, and there were no institutions promoting the implementation of social responsibility standards by companies. Research involving analysis of secondary data drawn from retailers’ websites, CSR reports, and published data relating to the CSR institutions allowed the following: (1) identification of three stages of development in consumers’ conception of CSR characterized by the immoral, amoral, and moral management; (2) showing that these activities have a business case; and (3) explaining the role of institutions and competition in this process. It is also shown how multinational retailers could contribute to the sustainable development of less mature markets in which they invest.Administrative Sciences2017-01-1471Article10.3390/admsci701000332076-33872017-01-14doi: 10.3390/admsci7010003Grażyna ŚmigielskaRenata Oczkowska<![CDATA[Algorithms, Vol. 10, Pages 14: Kernel Clustering with a Differential Harmony Search Algorithm for Scheme Classification]]>
http://www.mdpi.com/1999-4893/10/1/14
This paper presents a kernel fuzzy clustering with a novel differential harmony search algorithm to coordinate with the diversion scheduling scheme classification. First, we employed a self-adaptive solution generation strategy and differential evolution-based population update strategy to improve the classical harmony search. Second, we applied the differential harmony search algorithm to the kernel fuzzy clustering to help the clustering method obtain better solutions. Finally, the combination of the kernel fuzzy clustering and the differential harmony search is applied for water diversion scheduling in East Lake. A comparison of the proposed method with other methods has been carried out. The results show that the kernel clustering with the differential harmony search algorithm has good performance to cooperate with the water diversion scheduling problems.Algorithms2017-01-14101Article10.3390/a10010014141999-48932017-01-14doi: 10.3390/a10010014Yu FengJianzhong ZhouMuhammad Tayyab<![CDATA[Informatics, Vol. 4, Pages 4: Player–Game Interaction and Cognitive Gameplay: A Taxonomic Framework for the Core Mechanic of Videogames]]>
http://www.mdpi.com/2227-9709/4/1/4
Cognitive gameplay—the cognitive dimension of a player’s experience—emerges from the interaction between a player and a game. While its design requires careful consideration, cognitive gameplay can be designed only indirectly via the design of game components. In this paper, we focus on one such component—the core mechanic—which binds a player and game together through the performance of essential interactions. Little extant research has been aimed at developing frameworks to support the design of interactions within the core mechanic with cognitive gameplay in mind. We present a taxonomic framework named INFORM (Interaction desigN For the cORe Mechanic) to address this gap. INFORM employs twelve micro-level elements that collectively give structure to any individual interaction within the core mechanic. We characterize these elements in the context of videogames, and discuss their potential influences on cognitive gameplay. We situate these elements within a broader framework that synthesizes concepts relevant to game design. INFORM is a descriptive framework, and provides a common vocabulary and a set of concepts that designers can use to think systematically about issues related to micro-level interaction design and cognitive gameplay.Informatics2017-01-1341Article10.3390/informatics401000442227-97092017-01-13doi: 10.3390/informatics4010004Kamran SedigPaul ParsonsRobert Haworth<![CDATA[IJGI, Vol. 6, Pages 16: Joint Modeling of Multiple Crimes: A Bayesian Spatial Approach]]>
http://www.mdpi.com/2220-9964/6/1/16
A multivariate Bayesian spatial modeling approach was used to jointly model the counts of two types of crime, i.e., burglary and non-motor vehicle theft, and explore the geographic pattern of crime risks and relevant risk factors. In contrast to the univariate model, which assumes independence across outcomes, the multivariate approach takes into account potential correlations between crimes. Six independent variables are included in the model as potential risk factors. In order to fully present this method, both the multivariate model and its univariate counterpart are examined. We fitted the two models to the data and assessed them using the deviance information criterion. A comparison of the results from the two models indicates that the multivariate model was superior to the univariate model. Our results show that population density and bar density are clearly associated with both burglary and non-motor vehicle theft risks and indicate a close relationship between these two types of crime. The posterior means and 2.5% percentile of type-specific crime risks estimated by the multivariate model were mapped to uncover the geographic patterns. The implications, limitations and future work of the study are discussed in the concluding section.ISPRS International Journal of Geo-Information2017-01-1361Article10.3390/ijgi6010016162220-99642017-01-13doi: 10.3390/ijgi6010016Hongqiang LiuXinyan Zhu<![CDATA[Economies, Vol. 5, Pages 2: Acknowledgement to Reviewers of Economies in 2016]]>
http://www.mdpi.com/2227-7099/5/1/2
The editors of Economies would like to express their sincere gratitude to the following reviewers for assessing manuscripts in 2016.[...]Economies2017-01-1351Editorial10.3390/economies501000222227-70992017-01-13doi: 10.3390/economies5010002 Economies Editorial Office<![CDATA[Systems, Vol. 5, Pages 3: System-of-Systems Design Thinking on Behavior]]>
http://www.mdpi.com/2079-8954/5/1/3
Due to the increasing digitalization of all societal systems, informed design of services and systems becomes pertinent for various stakeholders. This paper discusses the design of digital systems in a user-centered way with the help of subject-oriented design. The approach follows a communication-driven and network-centric perspective on a System-of-Systems, whereby system specifications encapsulate behavior and exchange messages, including relevant data, such as business objects. Systems can represent activities of human actors, as well as artefacts. Stakeholders can be actively involved in their roles in the design of a System-of-Systems. In the course of design, they identify and refine role-specific behavior, based on communication to other actors or systems. A System-of-Systems specification evolves as a network of cooperating behavior entities. It develops according to communication needs and system-specific capabilities, on the level of synchronized execution agents, or as an overlay mechanism on existing applications or sub networks. Since certain behavior sequences, such as decision-making procedures, are re-occurring in organizations or eco-systems, the design of complex systems can be facilitated by behavior patterns stemming from existing modeling experiences.Systems2017-01-1351Article10.3390/systems501000332079-89542017-01-13doi: 10.3390/systems5010003Christian Stary<![CDATA[Symmetry, Vol. 9, Pages 10: Comparing Lifetimes of Series and Parallel Systems with Heterogeneous Fréchet Components]]>
http://www.mdpi.com/2073-8994/9/1/10
In this paper, we discuss stochastic comparisons of lifetimes of series and parallel systems with heterogeneous Fréchet components in terms of the usual stochastic order, reversed hazard rate order and likelihood ratio order. The partial results established here extend some well-known results in the literature of Gupta et al. Specifically, first, we generalize the result of Theorem 2 from the usual stochastic order to the reversed hazard rate order. Second, we generalize the result of Theorem 3 from the reversed hazard rate order to the likelihood ratio order. Last, we generalize the result of Theorem 4 from the hazard rate order to the likelihood ratio order when shape parameter 0 &lt; α ≤ 1 .Symmetry2017-01-1391Article10.3390/sym9010010102073-89942017-01-13doi: 10.3390/sym9010010Longxiang FangYanqin Wang<![CDATA[Algorithms, Vol. 10, Pages 12: Coupled Least Squares Identification Algorithms for Multivariate Output-Error Systems]]>
http://www.mdpi.com/1999-4893/10/1/12
This paper focuses on the recursive identification problems for a multivariate output-error system. By decomposing the system into several subsystems and by forming a coupled relationship between the parameter estimation vectors of the subsystems, two coupled auxiliary model based recursive least squares (RLS) algorithms are presented. Moreover, in contrast to the auxiliary model based recursive least squares algorithm, the proposed algorithms provide a reference to improve the identification accuracy of the multivariate output-error system. The simulation results confirm the effectiveness of the proposed algorithms.Algorithms2017-01-12101Article10.3390/a10010012121999-48932017-01-12doi: 10.3390/a10010012Wu HuangFeng Ding<![CDATA[Future Internet, Vol. 9, Pages 2: Acknowledgement to Reviewers of Future Internet in 2016]]>
http://www.mdpi.com/1999-5903/9/1/2
The editors of Future Internet would like to express their sincere gratitude to the following reviewers for assessing manuscripts in 2016.[...]Future Internet2017-01-1291Editorial10.3390/fi901000221999-59032017-01-12doi: 10.3390/fi9010002 Future Internet Editorial Office<![CDATA[IJGI, Vol. 6, Pages 15: How They Move Reveals What Is Happening: Understanding the Dynamics of Big Events from Human Mobility Pattern]]>
http://www.mdpi.com/2220-9964/6/1/15
The context in which a moving object moves contributes to the movement pattern observed. Likewise, the movement pattern reflects the properties of the movement context. In particular, big events influence human mobility depending on the dynamics of the events. However, this influence has not been explored to understand big events. In this paper, we propose a methodology for learning about big events from human mobility pattern. The methodology involves extracting and analysing the stopping, approaching, and moving-away interactions between public transportation vehicles and the geographic context. The analysis is carried out at two different temporal granularity levels to discover global and local patterns. The results of evaluating this methodology on bus trajectories demonstrate that it can discover occurrences of big events from mobility patterns, roughly estimate the event start and end time, and reveal the temporal patterns of arrival and departure of event attendees. This knowledge can be usefully applied in transportation and event planning and management.ISPRS International Journal of Geo-Information2017-01-1261Article10.3390/ijgi6010015152220-99642017-01-12doi: 10.3390/ijgi6010015Jean MazimpakaSabine Timpf<![CDATA[Symmetry, Vol. 9, Pages 11: Prognosis Essay Scoring and Article Relevancy Using Multi-Text Features and Machine Learning]]>
http://www.mdpi.com/2073-8994/9/1/11
This study develops a model for essay scoring and article relevancy. Essay scoring is a costly process when we consider the time spent by an evaluator. It may lead to inequalities of the effort by various evaluators to apply the same evaluation criteria. Bibliometric research uses the evaluation criteria to find relevancy of articles instead. Researchers mostly face relevancy issues while searching articles. Therefore, they classify the articles manually. However, manual classification is burdensome due to time needed for evaluation. The proposed model performs automatic essay evaluation using multi-text features and ensemble machine learning. The proposed method is implemented in two data sets: a Kaggle short answer data set for essay scoring that includes four ranges of disciplines (Science, Biology, English, and English language Arts), and a bibliometric data set having IoT (Internet of Things) and non-IoT classes. The efficacy of the model is measured against the Tandalla and AutoP approach using Cohen’s kappa. The model achieves kappa values of 0.80 and 0.83 for the first and second data sets, respectively. Kappa values show that the proposed model has better performance than those of earlier approaches.Symmetry2017-01-1291Article10.3390/sym9010011112073-89942017-01-12doi: 10.3390/sym9010011Arif MehmoodByung-Won OnIngyu LeeGyu Choi<![CDATA[Electronics, Vol. 6, Pages 9: A Modular Integrated RFID System for Inventory Control Applications]]>
http://www.mdpi.com/2079-9292/6/1/9
Recent advances in single-board computer technology have allowed for lightweight, power-efficient devices, such as the Raspberry Pi, to take the place of desktop PCs in certain applications. This has the potential to disrupt the way many current systems are structured, particularly for inventory management and control applications. In this paper, we explore the design and topology of a modular Radio frequency identification (RFID) system for inventory management comprised of self-contained, autonomous scanning, and stationary control PCs in a handheld/portable configuration. While similar solutions for such a system may exist on the commercial market, this proposed development provides a template for an open source flexible, low-cost solution that can be easily expanded to meet the needs of businesses with large and small inventories.Electronics2017-01-1261Article10.3390/electronics601000992079-92922017-01-12doi: 10.3390/electronics6010009Ross BunkerAtef Elsherbeni<![CDATA[Informatics, Vol. 4, Pages 3: Alt-Splice Gene Predictor Using Multitrack-Clique Analysis: Verification of Statistical Support for Modelling in Genomes of Multicellular Eukaryotes]]>
http://www.mdpi.com/2227-9709/4/1/3
One of the main limitations of the typical hidden Markov model (HMM) implementation for gene structure identification is that a single structure is identified on a given sequence of genomic data—i.e., identification of overlapping structure is not directly possible, and certainly not possible within the confines of the optimal Viterbi path evaluation. This is a huge limitation given that we now know that significant portions of eukaryotic genomes, particularly mammalian genomes, are alternatively spliced, and, thus, have overlapping structure in the sense of the mRNA transcripts that result. Using the general meta-state HMM approach developed in prior work, however, more than one ‘track’ of annotation can be accommodated, thereby allowing a direct implementation of an alternative-splice gene-structure identifier. In this paper we examine the representation of alternative splicing annotation in the multi-track context, and show that the proliferation on states is manageable, and has sufficient statistical support on the genomes examined (human, mouse, worm, and fly) that a full alt-splice meta-state HMM gene finder can be implemented with sufficient statistical support. In the process of performing the alternative splicing analysis on alt-splice event counts we expected to see an increase in alternative splicing complexity as the organism becomes more complex, and this is seen with the percentage of genes with alt-splice variants increasing from worm to fly to the mammalian genomes (mouse and human). Of particular note is an increase in alternative splicing variants at the start and end of coding with the more complex organisms studied (mouse and human), indicating rapid new first and last exon recruitment that is possibly spliceosome mediated. This suggests that spliceosome-mediated refinements (acceleration) of gene structure variation and selection, with increasing levels of sophistication, has occurred in eukaryotes and in mammals especially.Informatics2017-01-1241Article10.3390/informatics401000332227-97092017-01-12doi: 10.3390/informatics4010003Stephen Winters-HiltAndrew Lewis<![CDATA[IJGI, Vol. 6, Pages 13: A Combinatorial Reasoning Mechanism with Topological and Metric Relations for Change Detection in River Planforms: An Application to GlobeLand30’s Water Bodies]]>
http://www.mdpi.com/2220-9964/6/1/13
Changes in river plane shapes are called river planform changes (RPCs). Such changes can impact sustainable human development (e.g., human habitations, industrial and agricultural development, and national border security). RPCs can be identified through field surveys—a method that is highly precise but time-consuming, or through remote sensing (RS) and geographic information system (GIS), which are less precise but more efficient. Previous studies that have addressed RPCs often used RS, GIS, or digital elevation models (DEMs) and focused on only one or a few rivers in specific areas with the goal of identifying the reasons underlying these changes. In contrast, in this paper, we developed a combinatorial reasoning mechanism based on topological and metric relations that can be used to classify RPCs. This approach does not require DEMs and can eliminate most false-change information caused by varying river water levels. First, we present GIS models of river planforms based on their natural properties and, then, modify these models into simple GIS river planform models (SGRPMs) using straight lines rather than common lines to facilitate computational and human understanding. Second, we used double straight line 4-intersection models (DSL4IMs) and intersection and difference models (IDMs) of the regions to represent the topological relations between the SGRPMs and used double-start-point 8-distance models (DS8DMs) to express the metric relations between the SGRPMs. Then, we combined topological and metric relations to analyse the changes in the SGRPMs. Finally, to compensate for the complexity of common river planforms in nature, we proposed three segmentation rules to turn common river planforms into SGRPMs and used combinatorial reasoning mechanism tables (CRMTs) to describe the spatial relations among different river planforms. Based on our method, users can describe common river planforms and their changes in detail and confidently reject false changes. Future work should develop a method to automatically or semi-automatically adjust the segmentation rules and the combinatorial reasoning mechanism.ISPRS International Journal of Geo-Information2017-01-1261Article10.3390/ijgi6010013132220-99642017-01-12doi: 10.3390/ijgi6010013Liang LengGuodong YangShengbo Chen<![CDATA[IJGI, Vol. 6, Pages 14: UAV Low Altitude Photogrammetry for Power Line Inspection]]>
http://www.mdpi.com/2220-9964/6/1/14
When the distance between an obstacle and a power line is less than the discharge distance, a discharge arc can be generated, resulting in the interruption of power supplies. Therefore, regular safety inspections are necessary to ensure the safe operation of power grids. Tall vegetation and buildings are the key factors threatening the safe operation of extra high voltage transmission lines within a power line corridor. Manual or laser intensity direction and ranging (LiDAR) based inspections are time consuming and expensive. To make safety inspections more efficient and flexible, a low-altitude unmanned aerial vehicle (UAV) remote-sensing platform, equipped with an optical digital camera, was used to inspect power line corridors. We propose a semi-patch matching algorithm based on epipolar constraints, using both the correlation coefficient (CC) and the shape of its curve to extract three dimensional (3D) point clouds for a power line corridor. We use a stereo image pair from inter-strip to improve power line measurement accuracy by transforming the power line direction to an approximately perpendicular to epipolar line. The distance between the power lines and the 3D point cloud is taken as a criterion for locating obstacles within the power line corridor automatically. Experimental results show that our proposed method is a reliable, cost effective, and applicable way for practical power line inspection and can locate obstacles within the power line corridor with accuracy better than ±0.5 m.ISPRS International Journal of Geo-Information2017-01-1261Article10.3390/ijgi6010014142220-99642017-01-12doi: 10.3390/ijgi6010014Yong ZhangXiuxiao YuanYi FangShiyu Chen<![CDATA[MCA, Vol. 22, Pages 6: Acknowledgement to Reviewers of MCA in 2016]]>
http://www.mdpi.com/2297-8747/22/1/6
The editors of MCA would like to express their sincere gratitude to the following reviewers for assessing manuscripts in 2016.[...]Mathematical and Computational Applications2017-01-12221Editorial10.3390/mca2201000662297-87472017-01-12doi: 10.3390/mca22010006 MCA Editorial Office<![CDATA[Econometrics, Vol. 5, Pages 6: Between Institutions and Global Forces: Norwegian Wage Formation Since Industrialisation]]>
http://www.mdpi.com/2225-1146/5/1/6
This paper reviews the development of labour market institutions in Norway, shows how labour market regulation has been related to the macroeconomic development, and presents dynamic econometric models of nominal and real wages. Single equation and multi-equation models are reported. The econometric modelling uses a new data set with historical time series of wages and prices, unemployment and labour productivity. Impulse indicator saturation is used to achieve robust estimation of focus parameters, and the breaks are interpreted in the light of the historical overview. A relatively high degree of constancy of the key parameters of the wage setting equation is documented, over a considerably longer historical time period than earlier studies have done. The evidence is consistent with the view that the evolving system of collective labour market regulation over long periods has delivered a certain necessary level of coordination of wage and price setting. Nevertheless, there is also evidence that global forces have been at work for a long time, in a way that links real wages to productivity trends in the same way as in countries with very different institutions and macroeconomic development.Econometrics2017-01-1251Article10.3390/econometrics501000662225-11462017-01-12doi: 10.3390/econometrics5010006Ragnar Nymoen<![CDATA[Electronics, Vol. 6, Pages 8: Acknowledgement to Reviewers of Electronics in 2016]]>
http://www.mdpi.com/2079-9292/6/1/8
The editors of Electronics would like to express their sincere gratitude to the following reviewers for assessing manuscripts in 2016.[...]Electronics2017-01-1261Editorial10.3390/electronics601000882079-92922017-01-12doi: 10.3390/electronics6010008 Electronics Editorial Office<![CDATA[Risks, Vol. 5, Pages 4: Acknowledgement to Reviewers of Risks in 2016]]>
http://www.mdpi.com/2227-9091/5/1/4
The editors of Risks would like to express their sincere gratitude to the following reviewers for assessing manuscripts in 2016. [...]Risks2017-01-1251Editorial10.3390/risks501000442227-90912017-01-12doi: 10.3390/risks5010004 Risks Editorial Office<![CDATA[IJGI, Vol. 6, Pages 12: Towards a Common Framework for the Identification of Landforms on Terrain Models]]>
http://www.mdpi.com/2220-9964/6/1/12
A landform is a physical feature of the terrain with its own recognisable shape. Its definition is often qualitative and inherently vague. Hence, landforms are difficult to formalise in a logical model that can be implemented. We propose for that purpose a framework where these qualitative and vague definitions are transformed successively during different phases to yield an implementable data structure. Our main consideration is that landforms are characterised by salient elements as perceived by users. Hence, a common prototype based on an object-oriented approach is defined that shall apply to all landforms. This framework shall facilitate the definition of conceptual models for other landforms and relies on the use of ontology design patterns to express common elements and structures. The model is illustrated on examples from the literature, showing that existing works undertaken separately can be developed under a common framework.ISPRS International Journal of Geo-Information2017-01-1261Article10.3390/ijgi6010012122220-99642017-01-12doi: 10.3390/ijgi6010012Eric GuilbertBernard Moulin<![CDATA[Information, Vol. 8, Pages 10: Acknowledgement to Reviewers of Information in 2016]]>
http://www.mdpi.com/2078-2489/8/1/10
The editors of Information would like to express their sincere gratitude to the following reviewers for assessing manuscripts in 2016.[...]Information2017-01-1181Editorial10.3390/info8010010102078-24892017-01-11doi: 10.3390/info8010010Information Editorial Office<![CDATA[IJGI, Vol. 6, Pages 10: Fuzzy GML Modeling Based on Vague Soft Sets]]>
http://www.mdpi.com/2220-9964/6/1/10
The Open Geospatial Consortium (OGC) Geography Markup Language (GML) explicitly represents geographical spatial knowledge in text mode. All kinds of fuzzy problems will inevitably be encountered in spatial knowledge expression. Especially for those expressions in text mode, this fuzziness will be broader. Describing and representing fuzziness in GML seems necessary. Three kinds of fuzziness in GML can be found: element fuzziness, chain fuzziness, and attribute fuzziness. Both element fuzziness and chain fuzziness belong to the reflection of the fuzziness between GML elements and, then, the representation of chain fuzziness can be replaced by the representation of element fuzziness in GML. On the basis of vague soft set theory, two kinds of modeling, vague soft set GML Document Type Definition (DTD) modeling and vague soft set GML schema modeling, are proposed for fuzzy modeling in GML DTD and GML schema, respectively. Five elements or pairs, associated with vague soft sets, are introduced. Then, the DTDs and the schemas of the five elements are correspondingly designed and presented according to their different chains and different fuzzy data types. While the introduction of the five elements or pairs is the basis of vague soft set GML modeling, the corresponding DTD and schema modifications are key for implementation of modeling. The establishment of vague soft set GML enables GML to represent fuzziness and solves the problem of lack of fuzzy information expression in GML.ISPRS International Journal of Geo-Information2017-01-1161Article10.3390/ijgi6010010102220-99642017-01-11doi: 10.3390/ijgi6010010Bo WeiQingqing XieYuanyuan MengYao Zou<![CDATA[IJGI, Vol. 6, Pages 11: Acknowledgement to Reviewers of IJGI in 2016]]>
http://www.mdpi.com/2220-9964/6/1/11
The editors of IJGI would like to express their sincere gratitude to the following reviewers for assessing manuscripts in 2016.[...]ISPRS International Journal of Geo-Information2017-01-1161Editorial10.3390/ijgi6010011112220-99642017-01-11doi: 10.3390/ijgi6010011 IJGI Editorial Office<![CDATA[Infrastructures, Vol. 2, Pages 2: Quantifying the Financial Impact of Climate Change on Australian Local Government Roads]]>
http://www.mdpi.com/2412-3811/2/1/2
Australia’s 560 Councils are responsible for assets worth approximately $270 billion, many of which have a life span &gt;50 years and so will be affected by climate change. Maintenance and replacement of Council infrastructure is guided by principles, models and tools in the International Infrastructure Management Manual that currently do not allow for climate change impacts or the likely flow-on effects to asset and financial management. This paper describes a financial simulation model developed to calculate the financial impacts of climate change on three major asset classes of importance to Australian Councils: hotmix sealed, spray sealed and unsealed roads. The research goes beyond previous studies of climate change impacts on roads in that it provides a location specific toolkit that is designed to assist councils in their asset management and planned maintenance programmes. Two categories of inputs are required for the model: climate inputs, relating specifically to baseline temperature and rainfall distributions and climate change parameters for temperature and rainfall; and engineering inputs, relating specifically to the three road types and the key parameters of their performance and useful lives over the scenario period. The baseline distributions are then shifted mathematically within the model by the mean change as projected by a selected Global Climate Model (GCM) scenario. Outputs of the model are the historical baseline climate variable distributions and the climate change (CC) impacts on road performance are in the form of changes to the useful life of the asset and associated changes in asset resurfacing and rehabilitation costs. Ten case study local councils in southern Australia are examined. Using IPCC AR4 scenarios, the results suggest that the incremental impact of climate change on all three types of road infrastructure modelled will be generally low. There are small cost reductions over the period for all road types as a result of the expected drying and warming trends in the climate.Infrastructures2017-01-1121Article10.3390/infrastructures201000222412-38112017-01-11doi: 10.3390/infrastructures2010002Jacqueline BalstonSteven LiIvan IankovJon KellettGeoff Wells<![CDATA[IJFS, Vol. 5, Pages 3: Acknowledgement to Reviewers of the International Journal of Financial Studies in 2016]]>
http://www.mdpi.com/2227-7072/5/1/3
The editors of the International Journal of Financial Studies would like to express their sincere gratitude to the following reviewers for assessing manuscripts in 2016.[...]International Journal of Financial Studies2017-01-1151Editorial10.3390/ijfs501000332227-70722017-01-11doi: 10.3390/ijfs5010003 International Journal of Financial Studies Editorial Office<![CDATA[Axioms, Vol. 6, Pages 2: Acknowledgement to Reviewers of Axioms in 2016]]>
http://www.mdpi.com/2075-1680/6/1/2
n/aAxioms2017-01-1161Editorial10.3390/axioms601000222075-16802017-01-11doi: 10.3390/axioms6010002 Axioms Editorial Office<![CDATA[Infrastructures, Vol. 2, Pages 3: Toughness of Railroad Concrete Crossties with Holes and Web Openings]]>
http://www.mdpi.com/2412-3811/2/1/3
Prestressed concrete sleepers (or railroad ties) are principally designed in order to carry wheel loads from the rails to the ground of railway tracks, as well as to secure rail gauge for safe train travels. Their design takes into account static and dynamic loading conditions. In spite of prestressed concrete crossties being most commonly used in railway tracks, there have always been many demands from rail engineers to improve the serviceability and functionality of concrete crossties. For example, signaling, fiber optic, equipment cables are often damaged either by ballast corners or by the tamping machine. There has been a need to re-design concrete crossties to incorporate cables internally so that they would not experience detrimental or harsh environments. Also, many concrete crossties need a retrofit for an automatic train control device and similar signaling equipment. In contrast, the effects of holes and web openings on the structural capacity of concrete crossties have not been thoroughly investigated. This paper accordingly highlights the experimental investigations into the effect of holes and web openings on the toughness and ductility of concrete crossties. The key outcome of this research is to enable a better decision making process for retrofitting prestressed concrete crossties with holes and web openings in practice.Infrastructures2017-01-1121Technical Note10.3390/infrastructures201000332412-38112017-01-11doi: 10.3390/infrastructures2010003Erosha GamageSakdirat KaewunruenAlex RemennikovTetsuya Ishida<![CDATA[Safety, Vol. 3, Pages 6: Acknowledgement to Reviewers of Safety in 2016]]>
http://www.mdpi.com/2313-576X/3/1/6
n/aSafety2017-01-1131Editorial10.3390/safety301000662313-576X2017-01-11doi: 10.3390/safety3010006Safety Editorial Office<![CDATA[Econometrics, Vol. 5, Pages 7: Acknowledgement to Reviewers of Econometrics in 2016]]>
http://www.mdpi.com/2225-1146/5/1/7
The editors of Econometrics would like to express their sincere gratitude to the following reviewers for assessing manuscripts in 2016.[...]Econometrics2017-01-1151Editorial10.3390/econometrics501000772225-11462017-01-11doi: 10.3390/econometrics5010007 Econometrics Editorial Office<![CDATA[J. Imaging, Vol. 3, Pages 4: Comparison of Small Unmanned Aerial Vehicles Performance Using Image Processing]]>
http://www.mdpi.com/2313-433X/3/1/4
Precision agriculture is a farm management technology that involves sensing and then responding to the observed variability in the field. Remote sensing is one of the tools of precision agriculture. The emergence of small unmanned aerial vehicles (sUAV) have paved the way to accessible remote sensing tools for farmers. This paper describes the development of an image processing approach to compare two popular off-the-shelf sUAVs: 3DR Iris+ and DJI Phantom 2. Both units are equipped with a camera gimbal attached with a GoPro camera. The comparison of the two sUAV involves a hovering test and a rectilinear motion test. In the hovering test, the sUAV was allowed to hover over a known object and images were taken every quarter of a second for two minutes. For the image processing evaluation, the position of the object in the images was measured and this was used to assess the stability of the sUAV while hovering. In the rectilinear test, the sUAV was allowed to follow a straight path and images of a lined track were acquired. The lines on the images were then measured on how accurate the sUAV followed the path. The hovering test results show that the 3DR Iris+ had a maximum position deviation of 0.64 m (0.126 m root mean square RMS displacement) while the DJI Phantom 2 had a maximum deviation of 0.79 m (0.150 m RMS displacement). In the rectilinear motion test, the maximum displacement for the 3DR Iris+ and the DJI phantom 2 were 0.85 m (0.134 m RMS displacement) and 0.73 m (0.372 m RMS displacement). These results demonstrated that the two sUAVs performed well in both the hovering test and the rectilinear motion test and thus demonstrated that both sUAVs can be used for civilian applications such as agricultural monitoring. The results also showed that the developed image processing approach can be used to evaluate performance of a sUAV and has the potential to be used as another feedback control parameter for autonomous navigation.Journal of Imaging2017-01-1131Article10.3390/jimaging301000442313-433X2017-01-11doi: 10.3390/jimaging3010004Esteban CanoRyan HortonChase LiljegrenDuke Bulanon<![CDATA[Informatics, Vol. 4, Pages 2: Acknowledgement to Reviewers of Informatics in 2016]]>
http://www.mdpi.com/2227-9709/4/1/2
The editors of Informatics would like to express their sincere gratitude to the following reviewers for assessing manuscripts in 2016.[...]Informatics2017-01-1141Editorial10.3390/informatics401000222227-97092017-01-11doi: 10.3390/informatics4010002 Informatics Editorial Office<![CDATA[Computation, Vol. 5, Pages 8: Numerical and Computational Analysis of a New Vertical Axis Wind Turbine, Named KIONAS]]>
http://www.mdpi.com/2079-3197/5/1/8
This paper concentrates on a new configuration for a wind turbine, named KIONAS. The main purpose is to determine the performance and aerodynamic behavior of KIONAS, which is a vertical axis wind turbine with a stator over the rotor and a special feature in that it can consist of several stages. Notably, the stator is shaped in such a way that it increases the velocity of the air impacting the rotor blades. Moreover, each stage’s performance can be increased with the increase of the total number of stages. The effects of wind velocity, the various numbers of inclined rotor blades, the rotor diameter, the stator’s shape and the number of stages on the performance of KIONAS were studied. A FORTRAN code was developed in order to predict the power in several cases by solving the equations of continuity and momentum. Subsequently, further knowledge on the flow field was obtained by using a commercial Computational Fluid Dynamics code. Based on the results, it can be concluded that higher wind velocities and a greater number of blades produce more power. Furthermore, higher performance was found for a stator with curved guide vanes and for a KIONAS configuration with more stages.Computation2017-01-1151Article10.3390/computation501000882079-31972017-01-11doi: 10.3390/computation5010008Eleni DouviDimitra DouviDionissios MargarisIoannis Drosis<![CDATA[Information, Vol. 8, Pages 9: An Improved Particle Swarm Optimization-Based Feed-Forward Neural Network Combined with RFID Sensors to Indoor Localization]]>
http://www.mdpi.com/2078-2489/8/1/9
Location-based services (LBS) have long been recognized as a significant component of the emerging information services. However, the localization cost and the performance of algorithm still need to be optimized. In the study, an improved particle swarm optimization algorithm based on a feed-forward neural network (IMPSO-FNN) combined with RFID sensors is proposed, which can achieve the best indoor positioning location and overcome the problems effectively. In IMPSO-FNN, an improved PSO algorithm (IMPSO) is developed to determine the optimal connecting weights and markedly optimize the network parameters and structural parameters for the FNN, and then an optimal location prediction model is established by the IMPSO-FNN. To avoid the interference of environmental noise for the experimental data, some preprocessing methods are used during the positioning process. The computational results for learning two continuous functions show that the proposed positioning algorithm has a faster convergence rate and higher generalization performance. The model evaluation results also verify that the proposed positioning method really is superior to other algorithms in terms of the learning ability, efficiency, and positioning accuracy.Information2017-01-1181Article10.3390/info801000992078-24892017-01-11doi: 10.3390/info8010009Changzhi WangZhicai ShiFei Wu<![CDATA[Robotics, Vol. 6, Pages 1: Acknowledgement to Reviewers of Robotics in 2016]]>
http://www.mdpi.com/2218-6581/6/1/1
The editors of Robotics would like to express their sincere gratitude to the following reviewers for assessing manuscripts in 2016.[...]Robotics2017-01-1161Editorial10.3390/robotics601000112218-65812017-01-11doi: 10.3390/robotics6010001 Robotics Editorial Office<![CDATA[Data, Vol. 2, Pages 4: Acknowledgement to Reviewers of Data in 2016]]>
http://www.mdpi.com/2306-5729/2/1/4
The editors of Data would like to express their sincere gratitude to the following reviewers for assessing manuscripts in 2016.[...]Data2017-01-1121Editorial10.3390/data201000442306-57292017-01-11doi: 10.3390/data2010004Data Editorial Office<![CDATA[Fluids, Vol. 2, Pages 3: Acknowledgement to Reviewers of Fluids in 2016]]>
http://www.mdpi.com/2311-5521/2/1/3
The editors of Fluids would like to express their sincere gratitude to the following reviewers for assessing manuscripts in 2016.[...]Fluids2017-01-1121Editorial10.3390/fluids201000332311-55212017-01-11doi: 10.3390/fluids2010003Fluids Editorial Office<![CDATA[Systems, Vol. 5, Pages 2: Acknowledgement to Reviewers of Systems in 2016]]>
http://www.mdpi.com/2079-8954/5/1/2
n/aSystems2017-01-1151Editorial10.3390/systems501000222079-89542017-01-11doi: 10.3390/systems5010002 Systems Editorial Office<![CDATA[J. Imaging, Vol. 3, Pages 3: Acknowledgement to Reviewers of Journal of Imaging in 2016]]>
http://www.mdpi.com/2313-433X/3/1/3
The editors of Journal of Imaging would like to express their sincere gratitude to the following reviewers for assessing manuscripts in 2016.[...]Journal of Imaging2017-01-1131Editorial10.3390/jimaging301000332313-433X2017-01-11doi: 10.3390/jimaging3010003 J. Imaging Editorial Office<![CDATA[Computers, Vol. 6, Pages 2: Acknowledgement to Reviewers of Computers in 2016]]>
http://www.mdpi.com/2073-431X/6/1/2
The editors of Computers would like to express their sincere gratitude to the following reviewers for assessing manuscripts in 2016.[...]Computers2017-01-1161Editorial10.3390/computers601000222073-431X2017-01-11doi: 10.3390/computers6010002Computers Editorial Office<![CDATA[Administrative Sciences, Vol. 7, Pages 2: Acknowledgement to Reviewers of Administrative Sciences in 2016]]>
http://www.mdpi.com/2076-3387/7/1/2
The editors of Administrative Sciences would like to express their sincere gratitude to the following reviewers for assessing manuscripts in 2016.[...]Administrative Sciences2017-01-1071Editorial10.3390/admsci701000222076-33872017-01-10doi: 10.3390/admsci7010002 Administrative Sciences Editorial Office<![CDATA[Electronics, Vol. 6, Pages 7: High-Speed Non-Volatile Optical Memory: Achievements and Challenges]]>
http://www.mdpi.com/2079-9292/6/1/7
We have proposed, fabricated, and studied a new design of a high-speed optical non-volatile memory. The recoding mechanism of the proposed memory utilizes a magnetization reversal of a nanomagnet by a spin-polarized photocurrent. It was shown experimentally that the operational speed of this memory may be extremely fast above 1 TBit/s. The challenges to realize both a high-speed recording and a high-speed reading are discussed. The memory is compact, integratable, and compatible with present semiconductor technology. If realized, it will advance data processing and computing technology towards a faster operation speed.Electronics2017-01-1061Article10.3390/electronics601000772079-92922017-01-10doi: 10.3390/electronics6010007Vadym Zayets<![CDATA[Technologies, Vol. 5, Pages 5: Acknowledgement to Reviewers of Technologies in 2016]]>
http://www.mdpi.com/2227-7080/5/1/5
The editors of Technologies would like to express their sincere gratitude to the following reviewers for assessing manuscripts in 2016.[...]Technologies2017-01-1051Editorial10.3390/technologies501000552227-70802017-01-10doi: 10.3390/technologies5010005Technologies Editorial Office<![CDATA[JSAN, Vol. 6, Pages 1: Acknowledgement to Reviewers of JSAN in 2016]]>
http://www.mdpi.com/2224-2708/6/1/1
The editors of JSAN would like to express their sincere gratitude to the following reviewers for assessing manuscripts in 2016.[...]Journal of Sensor and Actuator Networks2017-01-1061Editorial10.3390/jsan601000112224-27082017-01-10doi: 10.3390/jsan6010001JSAN Editorial Office<![CDATA[Algorithms, Vol. 10, Pages 11: Acknowledgement to Reviewers of Algorithms in 2016]]>
http://www.mdpi.com/1999-4893/10/1/11
The editors of Algorithms would like to express their sincere gratitude to the following reviewers for assessing manuscripts in 2016.[...]Algorithms2017-01-10101Editorial10.3390/a10010011111999-48932017-01-10doi: 10.3390/a10010011 Algorithms Editorial Office<![CDATA[Computation, Vol. 5, Pages 7: Acknowledgement to Reviewers of Computation in 2016]]>
http://www.mdpi.com/2079-3197/5/1/7
The editors of Computation would like to express their sincere gratitude to the following reviewers for assessing manuscripts in 2016.[...]Computation2017-01-1051Editorial10.3390/computation501000772079-31972017-01-10doi: 10.3390/computation5010007 Computation Editorial Office<![CDATA[JRFM, Vol. 10, Pages 2: Acknowledgement to Reviewers of the Journal of Risk and Financial Management in 2016]]>
http://www.mdpi.com/1911-8074/10/1/2
The editors of the Journal of Risk and Financial Management would like to express their sincere gratitude to the following reviewers for assessing manuscripts in 2016.[...]Journal of Risk and Financial Management2017-01-10101Editorial10.3390/jrfm1001000221911-80742017-01-10doi: 10.3390/jrfm10010002 JRFM Editorial Office<![CDATA[Computation, Vol. 5, Pages 6: Towards a Multiscale Model of Acute HIV Infection]]>
http://www.mdpi.com/2079-3197/5/1/6
Human Immunodeficiency Virus (HIV) infection of humans represents a complex biological system and a great challenge to public health. Novel approaches for the analysis and prediction of the infection dynamics based on a multi-scale integration of virus ontogeny and immune reactions are needed to deal with the systems’ complexity. The aim of our study is: (1) to formulate a multi-scale mathematical model of HIV infection; (2) to implement the model computationally following a hybrid approach; and (3) to calibrate the model by estimating the parameter values enabling one to reproduce the “standard” observed dynamics of HIV infection in blood during the acute phase of primary infection. The modeling approach integrates the processes of infection spread and immune responses in Lymph Nodes (LN) to that observed in blood. The spatio-temporal population dynamics of T lymphocytes in LN in response to HIV infection is governed by equations linking an intracellular regulation of the lymphocyte fate by intercellular cytokine fields. We describe the balance of proliferation, differentiation and death at a single cell level as a consequence of gene activation via multiple signaling pathways activated by IL-2, IFNa and FasL. Distinct activation thresholds are used in the model to relate different modes of cellular responses to the hierarchy of the relative levels of the cytokines. We specify a reference set of model parameter values for the fundamental processes in lymph nodes that ensures a reasonable agreement with viral load and CD4+ T cell dynamics in blood.Computation2017-01-1051Article10.3390/computation501000662079-31972017-01-10doi: 10.3390/computation5010006Anass BouchnitaGennady BocharovAndreas MeyerhansVitaly Volpert<![CDATA[IJGI, Vol. 6, Pages 9: Terrain Extraction in Built-Up Areas from Satellite Stereo-Imagery-Derived Surface Models: A Stratified Object-Based Approach]]>
http://www.mdpi.com/2220-9964/6/1/9
Very high spatial resolution (VHSR) stereo-imagery-derived digital surface models (DSM) can be used to generate digital elevation models (DEM). Filtering algorithms and triangular irregular network (TIN) densification are the most common approaches. Most filter-based techniques focus on image-smoothing. We propose a new approach which makes use of integrated object-based image analysis (OBIA) techniques. An initial land cover classification is followed by stratified land cover ground point sample detection, using object-specific features to enhance the sampling quality. The detected ground point samples serve as the basis for the interpolation of the DEM. A regional uncertainty index (RUI) is calculated to express the quality of the generated DEM in regard to the DSM, based on the number of samples per land cover object. The results of our approach are compared to a high resolution Light Detection and Ranging (LiDAR)-DEM, and a high level of agreement is observed—especially for non-vegetated and scarcely-vegetated areas. Results show that the accuracy of the DEM is highly dependent on the quality of the initial DSM and—in accordance with the RUI—differs between the different land cover classes.ISPRS International Journal of Geo-Information2017-01-1061Article10.3390/ijgi601000992220-99642017-01-10doi: 10.3390/ijgi6010009Fritjof LuethjeDirk TiedeClemens Eisank<![CDATA[Algorithms, Vol. 10, Pages 8: Modeling Delayed Dynamics in Biological Regulatory Networks from Time Series Data]]>
http://www.mdpi.com/1999-4893/10/1/8
Background: The modeling of Biological Regulatory Networks (BRNs) relies on background knowledge, deriving either from literature and/or the analysis of biological observations. However, with the development of high-throughput data, there is a growing need for methods that automatically generate admissible models. Methods: Our research aim is to provide a logical approach to infer BRNs based on given time series data and known influences among genes. Results: We propose a new methodology for models expressed through a timed extension of the automata networks (well suited for biological systems). The main purpose is to have a resulting network as consistent as possible with the observed datasets. Conclusion: The originality of our work is three-fold: (i) identifying the sign of the interaction; (ii) the direct integration of quantitative time delays in the learning approach; and (iii) the identification of the qualitative discrete levels that lead to the systems’ dynamics. We show the benefits of such an automatic approach on dynamical biological models, the DREAM4(in silico) and DREAM8 (breast cancer) datasets, popular reverse-engineering challenges, in order to discuss the precision and the computational performances of our modeling method.Algorithms2017-01-09101Article10.3390/a1001000881999-48932017-01-09doi: 10.3390/a10010008Emna Ben AbdallahTony RibeiroMorgan MagninOlivier RouxKatsumi Inoue<![CDATA[Algorithms, Vol. 10, Pages 10: Estimating the Local Radius of Convergence for Picard Iteration]]>
http://www.mdpi.com/1999-4893/10/1/10
In this paper, we propose an algorithm to estimate the radius of convergence for the Picard iteration in the setting of a real Hilbert space. Numerical experiments show that the proposed algorithm provides convergence balls close to or even identical to the best ones. As the algorithm does not require to evaluate the norm of derivatives, the computing effort is relatively low.Algorithms2017-01-09101Article10.3390/a10010010101999-48932017-01-09doi: 10.3390/a10010010Ştefan Măruşter<![CDATA[IJGI, Vol. 6, Pages 8: An On-Demand Retrieval Method Based on Hybrid NoSQL for Multi-Layer Image Tiles in Disaster Reduction Visualization]]>
http://www.mdpi.com/2220-9964/6/1/8
Monitoring, response, mitigation and damage assessment of disasters places a wide variety of demands on the spatial and temporal resolutions of remote sensing images. Images are divided into tile pyramids by data sources or resolutions and published as independent image services for visualization. A disaster-affected area is commonly covered by multiple image layers to express hierarchical surface information, which generates a large amount of namesake tiles from different layers that overlay the same location. The traditional tile retrieval method for visualization cannot distinguish between distinct layers and traverses all image datasets for each tile query. This process produces redundant queries and invalid access that can seriously affect the visualization performance of clients, servers and network transmission. This paper proposes an on-demand retrieval method for multi-layer images and defines semantic annotations to enrich the description of each dataset. By matching visualization demands with the semantic information of datasets, this method automatically filters inappropriate layers and finds the most suitable layer for the final tile query. The design and implementation are based on a two-layer NoSQL database architecture that provides scheduling optimization and concurrent processing capability. The experimental results reflect the effectiveness and stability of the approach for multi-layer retrieval in disaster reduction visualization.ISPRS International Journal of Geo-Information2017-01-0961Article10.3390/ijgi601000882220-99642017-01-09doi: 10.3390/ijgi6010008Linyao QiuQing ZhuZhiqiang DuMeng WangYida Fan<![CDATA[Symmetry, Vol. 9, Pages 8: DIaaS: Resource Management System for the Intra-Cloud with On-Premise Desktops]]>
http://www.mdpi.com/2073-8994/9/1/8
Infrastructure as a service with desktops (DIaaS) based on the extensible mark-up language (XML) is herein proposed to utilize surplus resources. DIaaS is a traditional surplus-resource integrated management technology. It is designed to provide fast work distribution and computing services based on user service requests as well as storage services through desktop-based distributed computing and storage resource integration. DIaaS includes a nondisruptive resource service and an auto-scalable scheme to enhance the availability and scalability of intra-cloud computing resources. A performance evaluation of the proposed scheme measured the clustering performance time for surplus resource utilization. The results showed improvement in computing and storage services in a connection of at least two computers compared to the traditional method for high-availability measurement of nondisruptive services. Furthermore, an artificial server error environment was used to create a clustering delay for computing and storage services and for nondisruptive services. It was compared to the Hadoop distributed file system (HDFS).Symmetry2017-01-0991Article10.3390/sym901000882073-89942017-01-09doi: 10.3390/sym9010008Hyun-Woo KimJaekyung HanJong ParkYoung-Sik Jeong<![CDATA[Econometrics, Vol. 5, Pages 5: Fractional Unit Root Tests Allowing for a Structural Change in Trend under Both the Null and Alternative Hypotheses]]>
http://www.mdpi.com/2225-1146/5/1/5
This paper considers testing procedures for the null hypothesis of a unit root process against the alternative of a fractional process, called a fractional unit root test. We extend the Lagrange Multiplier (LM) tests of Robinson (1994) and Tanaka (1999), which are locally best invariant and uniformly most powerful, to allow for a slope change in trend with or without a concurrent level shift under both the null and alternative hypotheses. We show that the limit distribution of the proposed LM tests is standard normal. Finite sample simulation experiments show that the tests have good size and power. As an empirical analysis, we apply the tests to the Consumer Price Indices of the G7 countries.Econometrics2017-01-0851Article10.3390/econometrics501000552225-11462017-01-08doi: 10.3390/econometrics5010005Seong ChangPierre Perron<![CDATA[Algorithms, Vol. 10, Pages 9: Elite Opposition-Based Social Spider Optimization Algorithm for Global Function Optimization]]>
http://www.mdpi.com/1999-4893/10/1/9
The Social Spider Optimization algorithm (SSO) is a novel metaheuristic optimization algorithm. To enhance the convergence speed and computational accuracy of the algorithm, in this paper, an elite opposition-based Social Spider Optimization algorithm (EOSSO) is proposed; we use an elite opposition-based learning strategy to enhance the convergence speed and computational accuracy of the SSO algorithm. The 23 benchmark functions are tested, and the results show that the proposed elite opposition-based Social Spider Optimization algorithm is able to obtain an accurate solution, and it also has a fast convergence speed and a high degree of stability.Algorithms2017-01-08101Article10.3390/a1001000991999-48932017-01-08doi: 10.3390/a10010009Ruxin ZhaoQifang LuoYongquan Zhou<![CDATA[Safety, Vol. 3, Pages 5: Alcohol Inhibits Organic Dust-Induced ICAM-1 Expression on Bronchial Epithelial Cells]]>
http://www.mdpi.com/2313-576X/3/1/5
Aims: Exposure to dusts/bioaerosols in concentrated animal feeding operations (CAFOs) results in inflammatory lung diseases in workers. Hog CAFOs dust extract (HDE) increases expression of intercellular adhesion molecule-1 (ICAM-1), neutrophil adhesion, and TNFα release in bronchial epithelial cells. Alcohol consumption is increasingly recognized to impair lung immunity. We hypothesized that alcohol impairs HDE-induced TNFα, ICAM-1 expression, and neutrophil adhesion by directly inhibiting TNFα converting enzyme (TACE) activity. Methods: Bronchial epithelial cells (BEAS-2B) and primary human bronchial epithelial cells were pretreated with ethanol (EtOH) or TACE inhibitor. ICAM-1 surface expression; TNFα release; and TACE activity were analyzed following HDE stimulation. The effect of alcohol and TACE inhibition on HDE-regulated epithelial cell/neutrophil adhesion interactions was investigated. Finally; utilizing an established animal model; C57BL/6 mice were fed ad libitum ethanol (20%) in drinking water for 8 weeks followed by daily intranasal inhalation of HDE or saline during the final two weeks. Mice were sacrificed and lung sections immunostained for ICAM-1. Results: Pretreatment with alcohol or TACE inhibitor significantly decreased HDE-induced ICAM-1 expression and TNFα release. HDE augmented neutrophil adhesion to epithelial cells, which was decreased with alcohol (32% decrease) or TACE inhibitor (55% decrease) pretreatment. TACE activity increased following HDE exposure, but TACE activity was inhibited following alcohol pretreatment. Alcohol-fed mice demonstrated decreased HDE-induced airway epithelium ICAM-1 expression. Conclusions: Alcohol diminishes HDE-induced ICAM-1 expression, TNFα release, and neutrophil adhesion via inhibition of TACE activity. These results suggest that alcohol may be an important modulator of lung innate immune responses following CAFO exposure.Safety2017-01-0731Article10.3390/safety301000552313-576X2017-01-07doi: 10.3390/safety3010005Todd WyattKerry CanadyArt HeiresJill PooleKristina BaileyTara NordgrenDebra Romberger<![CDATA[Symmetry, Vol. 9, Pages 9: Improved Asymmetric Cipher Based on Matrix Power Function with Provable Security]]>
http://www.mdpi.com/2073-8994/9/1/9
The improved version of the author’s previously declared asymmetric cipher protocol based on matrix power function (MPF) is presented. Proposed modification avoids discrete logarithm attack (DLA) which could be applied to the previously declared protocol. This attack allows us to transform the initial system of MPF equations to so-called matrix multivariate quadratic (MMQ) system of equations, which is a system representing a subclass of multivariate quadratic (MQ) systems of equations. We are making a conjecture that avoidance of DLA in protocol, presented here, should increase its security, since an attempt to solve the initial system of MPF equations would appear to be no less complex than solving the system of MMQ equations. No algorithms are known to solve such a system of equations. Security parameters and their secure values are defined. Security analysis against chosen plaintext attack (CPA) and chosen ciphertext attack (CCA) is presented. Measures taken to prevent DLA attack increase the security of this protocol with respect to the previously declated protocol.Symmetry2017-01-0791Article10.3390/sym901000992073-89942017-01-07doi: 10.3390/sym9010009Eligijus SakalauskasAleksejus MihalkovichAlgimantas Venčkauskas<![CDATA[Mathematics, Vol. 5, Pages 4: Logical Entropy of Dynamical Systems—A General Model]]>
http://www.mdpi.com/2227-7390/5/1/4
In the paper by Riečan and Markechová (Fuzzy Sets Syst. 96, 1998), some fuzzy modifications of Shannon’s and Kolmogorov-Sinai’s entropy were studied and the general scheme involving the presented models was introduced. Our aim in this contribution is to provide analogies of these results for the case of the logical entropy. We define the logical entropy and logical mutual information of finite partitions on the appropriate algebraic structure and prove basic properties of these measures. It is shown that, as a special case, we obtain the logical entropy of fuzzy partitions studied by Markechová and Riečan (Entropy 18, 2016). Finally, using the suggested concept of entropy of partitions we define the logical entropy of a dynamical system and prove that it is the same for two dynamical systems that are isomorphic.Mathematics2017-01-0651Article10.3390/math501000442227-73902017-01-06doi: 10.3390/math5010004Abolfazl EbrahimzadehZahra GiskiDagmar Markechová<![CDATA[IJGI, Vol. 6, Pages 7: Understanding the Representativeness of Mobile Phone Location Data in Characterizing Human Mobility Indicators]]>
http://www.mdpi.com/2220-9964/6/1/7
The advent of big data has aided understanding of the driving forces of human mobility, which is beneficial for many fields, such as mobility prediction, urban planning, and traffic management. However, the data sources used in many studies, such as mobile phone location and geo-tagged social media data, are sparsely sampled in the temporal scale. An individual’s records can be distributed over a few hours a day, or a week, or over just a few hours a month. Thus, the representativeness of sparse mobile phone location data in characterizing human mobility requires analysis before using data to derive human mobility patterns. This paper investigates this important issue through an approach that uses subscriber mobile phone location data collected by a major carrier in Shenzhen, China. A dataset of over 5 million mobile phone subscribers that covers 24 h a day is used as a benchmark to test the representativeness of mobile phone location data on human mobility indicators, such as total travel distance, movement entropy, and radius of gyration. This study divides this dataset by hour, using 2- to 23-h segments to evaluate the representativeness due to the availability of mobile phone location data. The results show that different numbers of hourly segments affect estimations of human mobility indicators and can cause overestimations or underestimations from the individual perspective. On average, the total travel distance and movement entropy tend to be underestimated. The underestimation coefficient results for estimation of total travel distance are approximately linear, declining as the number of time segments increases, and the underestimation coefficient results for estimating movement entropy decline logarithmically as the time segments increase, whereas the radius of gyration tends to be more ambiguous due to the loss of isolated locations. This paper suggests that researchers should carefully interpret results derived from this type of sparse data in the era of big data.ISPRS International Journal of Geo-Information2017-01-0661Article10.3390/ijgi601000772220-99642017-01-06doi: 10.3390/ijgi6010007Shiwei LuZhixiang FangXirui ZhangShih-Lung ShawLing YinZhiyuan ZhaoXiping Yang<![CDATA[Algorithms, Vol. 10, Pages 7: Backtracking-Based Iterative Regularization Method for Image Compressive Sensing Recovery]]>
http://www.mdpi.com/1999-4893/10/1/7
This paper presents a variant of the iterative shrinkage-thresholding (IST) algorithm, called backtracking-based adaptive IST (BAIST), for image compressive sensing (CS) reconstruction. For increasing iterations, IST usually yields a smoothing of the solution and runs into prematurity. To add back more details, the BAIST method backtracks to the previous noisy image using L2 norm minimization, i.e., minimizing the Euclidean distance between the current solution and the previous ones. Through this modification, the BAIST method achieves superior performance while maintaining the low complexity of IST-type methods. Also, BAIST takes a nonlocal regularization with an adaptive regularizor to automatically detect the sparsity level of an image. Experimental results show that our algorithm outperforms the original IST method and several excellent CS techniques.Algorithms2017-01-06101Article10.3390/a1001000771999-48932017-01-06doi: 10.3390/a10010007Lingjun LiuZhonghua XieJiuchao Feng<![CDATA[Risks, Vol. 5, Pages 3: The Effects of Largest Claim and Excess of Loss Reinsurance on a Company’s Ruin Time and Valuation]]>
http://www.mdpi.com/2227-9091/5/1/3
We compare two types of reinsurance: excess of loss (EOL) and largest claim reinsurance (LCR), each of which transfers the payment of part, or all, of one or more large claims from the primary insurance company (the cedant) to a reinsurer. The primary insurer’s point of view is documented in terms of assessment of risk and payment of reinsurance premium. A utility indifference rationale based on the expected future dividend stream is used to value the company with and without reinsurance. Assuming the classical compound Poisson risk model with choices of claim size distributions (classified as heavy, medium and light-tailed cases), simulations are used to illustrate the impact of the EOL and LCR treaties on the company’s ruin probability, ruin time and value as determined by the dividend discounting model. We find that LCR is at least as effective as EOL in averting ruin in comparable finite time horizon settings. In instances where the ruin probability for LCR is smaller than for EOL, the dividend discount model shows that the cedant is able to pay a larger portion of the dividend for LCR reinsurance than for EOL while still maintaining company value. Both methods reduce risk considerably as compared with no reinsurance, in a variety of situations, as measured by the standard deviation of the company value. A further interesting finding is that heaviness of tails alone is not necessarily the decisive factor in the possible ruin of a company; small and moderate sized claims can also play a significant role in this.Risks2017-01-0651Article10.3390/risks501000332227-90912017-01-06doi: 10.3390/risks5010003Yuguang FanPhilip GriffinRoss MallerAlexander SzimayerTiandong Wang<![CDATA[Symmetry, Vol. 9, Pages 7: First and Second Zagreb Eccentricity Indices of Thorny Graphs]]>
http://www.mdpi.com/2073-8994/9/1/7
The Zagreb eccentricity indices are the eccentricity reformulation of the Zagreb indices. Let H be a simple graph. The first Zagreb eccentricity index ( E 1 ( H ) ) is defined to be the summation of squares of the eccentricity of vertices, i.e., E 1 ( H ) = ∑ u ∈ V ( H ) Ɛ H 2 ( u ) . The second Zagreb eccentricity index ( E 2 ( H ) ) is the summation of product of the eccentricities of the adjacent vertices, i.e., E 2 ( H ) = ∑ u v ∈ E ( H ) Ɛ H ( u ) Ɛ H ( v ) . We obtain the thorny graph of a graph H by attaching thorns i.e., vertices of degree one to every vertex of H . In this paper, we will find closed formulation for the first Zagreb eccentricity index and second Zagreb eccentricity index of different well known classes of thorny graphs.Symmetry2017-01-0691Article10.3390/sym901000772073-89942017-01-06doi: 10.3390/sym9010007Nazeran IdreesMuhammad SaifAsia RaufSaba Mustafa<![CDATA[J. Imaging, Vol. 3, Pages 2: Peach Flower Monitoring Using Aerial Multispectral Imaging]]>
http://www.mdpi.com/2313-433X/3/1/2
One of the tools for optimal crop production is regular monitoring and assessment of crops. During the growing season of fruit trees, the bloom period has increased photosynthetic rates that correlate with the fruiting process. This paper presents the development of an image processing algorithm to detect peach blossoms on trees. Aerial images of peach (Prunus persica) trees were acquired from both experimental and commercial peach orchards in the southwestern part of Idaho using an off-the-shelf unmanned aerial system (UAS), equipped with a multispectral camera (near-infrared, green, blue). The image processing algorithm included contrast stretching of the three bands to enhance the image and thresholding segmentation method to detect the peach blossoms. Initial results showed that the image processing algorithm could detect peach blossoms with an average detection rate of 84.3% and demonstrated good potential as a monitoring tool for orchard management.Journal of Imaging2017-01-0631Article10.3390/jimaging301000222313-433X2017-01-06doi: 10.3390/jimaging3010002Ryan HortonEsteban CanoDuke BulanonEsmaeil Fallahi<![CDATA[Systems, Vol. 5, Pages 1: Investigating the Users’ Approach to ICT Platforms in the City Management]]>
http://www.mdpi.com/2079-8954/5/1/1
The increasing relevance of technology and its impact on our everyday life requires multi- and trans-disciplinary studies in order to investigate the ways in which the Information and Communication Technology (ICT) tools are affected by users’ features and by the external environment. In order to enrich existing contributions on this topic, the paper focuses its attention on the city as example of service systems, in order to investigate dimensions and dynamics that influence the city employees’ evaluation and satisfaction in the use of ICT platforms. By adopting the interpretative lens offered by Service Science and Systems Thinking, the domain of city as a service system is analysed and some hypotheses are formulated with reference to the relationships between environment, users, and ICT platform. The hypotheses are investigated through a questionnaire survey on a sample of 1032 municipalities in the Czech Republic and the results are tested using Structural Equation Modelling. The research shows that users’ features and external environment affect the evaluation and the satisfaction of city stakeholders about the use of ICT platforms by underlining the need for enlarging the study on informatics tools, in order to also include subjective variables. The findings are discussed from both theoretical and practical points of view.Systems2017-01-0651Article10.3390/systems501000112079-89542017-01-06doi: 10.3390/systems5010001Francesco CaputoLeonard Walletzký<![CDATA[Mathematics, Vol. 5, Pages 5: Data Clustering with Quantum Mechanics]]>
http://www.mdpi.com/2227-7390/5/1/5
Data clustering is a vital tool for data analysis. This work shows that some existing useful methods in data clustering are actually based on quantum mechanics and can be assembled into a powerful and accurate data clustering method where the efficiency of computational quantum chemistry eigenvalue methods is therefore applicable. These methods can be applied to scientific data, engineering data and even text.Mathematics2017-01-0651Article10.3390/math501000552227-73902017-01-06doi: 10.3390/math5010005Tony ScottMadhusudan TheraniXing Wang<![CDATA[Mathematics, Vol. 5, Pages 3: From the Underdamped Generalized Elastic Model to the Single Particle Langevin Description]]>
http://www.mdpi.com/2227-7390/5/1/3
The generalized elastic model encompasses several linear stochastic models describing the dynamics of polymers, membranes, rough surfaces, and fluctuating interfaces. While usually defined in the overdamped case, in this paper we formally include the inertial term to account for the initial diffusive stages of the stochastic dynamics. We derive the generalized Langevin equation for a probe particle and we show that this equation reduces to the usual Langevin equation for Brownian motion, and to the fractional Langevin equation on the long-time limit.Mathematics2017-01-0651Article10.3390/math501000332227-73902017-01-06doi: 10.3390/math5010003Alessandro Taloni<![CDATA[Mathematics, Vol. 5, Pages 2: On Autonomy Imposition in Zero Interval Limit Perturbation Expansion for the Spectral Entities of Hilbert–Schmidt Integral Operators]]>
http://www.mdpi.com/2227-7390/5/1/2
In this work, we deal with the autonomy issue in the perturbation expansion for the eigenfunctions of a compact Hilbert–Schmidt integral operator. Here, the autonomy points to the perturbation expansion coefficients of the relevant eigenfunction not depending on the perturbation parameter explicitly, but the dependence on this parameter arises from the coordinate change at the zero interval limit. Moreover, the related half interval length is utilized as the perturbation parameter in the perturbative analyses. Thus, the zero interval limit perturbation for solving the eigenproblem under consideration is developed. The aim of this work is to show that the autonomy imposition brings an important restriction on the kernel of the corresponding integral operator, and the constructed perturbation series is not capable of expressing the exact solution approximately unless a specific type of kernel is considered. The general structure for the encountered constraints is revealed, and the specific class of kernels is identified to this end. Error analysis of the developed method is given. These analyses are also supported by certain illustrative implementations involving the kernels, which are and are not in the specific class addressed above. Thus, the efficiency of the developed method is shown, and the relevant analyses are confirmed.Mathematics2017-01-0651Article10.3390/math501000222227-73902017-01-06doi: 10.3390/math5010002Süha TunaMetin Demiralp<![CDATA[Fluids, Vol. 2, Pages 2: RANS Simulations of Aerodynamic Performance of NACA 0015 Flapped Airfoil]]>
http://www.mdpi.com/2311-5521/2/1/2
An analysis of 2D subsonic flow over an NACA 0015 airfoil with a 30% trailing edge flap at a constant Reynolds number of 106 for various incidence angles and a range of flap deflections is presented. The steady-state governing equations of continuity and momentum conservation are solved combined with the realizable k-ε turbulence model using the ANSYS-Fluent code (Version 13.7, ANSYS, Inc., Canonsburg, PA, USA). The primary objective of the study is to provide a comprehensive understanding of flow characteristics around the NACA 0015 airfoil as a function of the angle of attack and flap deflection at Re = 106 using the realizable k-ε turbulence model. The results are validated through comparison of the predictions with the free field experimental measurements. Consistent with the experimental observations, the numerical results show that increased flap deflections increase the maximum lift coefficient, move the zero-lift angle of attack (AoA) to a more negative value, decrease the stall AoA, while the slope of the lift curve remains unchanged and the curve just shifts upwards. In addition, the numerical simulations provide limits for lift increment Δ C l and Cl, max values to be 1.1 and 2.2, respectively, obtained at a flap deflection of 50°. This investigation demonstrates that the realizable k-ε turbulence model is capable of predicting flow features over an airfoil with and without flap deflections with reasonable accuracy.Fluids2017-01-0521Article10.3390/fluids201000222311-55212017-01-05doi: 10.3390/fluids2010002Sohaib ObeidRatneshwar JhaGoodarz Ahmadi<![CDATA[Cryptography, Vol. 1, Pages 4: Cryptography in Wireless Multimedia Sensor Networks: A Survey and Research Directions]]>
http://www.mdpi.com/2410-387X/1/1/4
Wireless multimedia sensor networks will play a central role in the Internet of Things world, providing content-rich information for an uncountable number of monitoring and control scenarios. As more applications rely on multimedia data, security concerns gain attention, and new approaches arise to provide security for such networks. However, the usual resource constraints of processing, memory and the energy of multimedia-based sensors have brought different challenges for data encryption, which have driven the development of different security approaches. In this context, this article presents the state-of-the-art of cryptography in wireless multimedia sensor networks, surveying innovative works in this area and discussing promising research directions.Cryptography2017-01-0511Review10.3390/cryptography101000442410-387X2017-01-05doi: 10.3390/cryptography1010004Daniel CostaSolenir FiguerêdoGledson Oliveira<![CDATA[Econometrics, Vol. 5, Pages 1: Business Cycle Estimation with High-Pass and Band-Pass Local Polynomial Regression]]>
http://www.mdpi.com/2225-1146/5/1/1
Filters constructed on the basis of standard local polynomial regression (LPR) methods have been used in the literature to estimate the business cycle. We provide a frequency domain interpretation of the contrast filter obtained by the difference of a series and its long-run LPR component and show that it operates as a kind of high-pass filter, so that it provides a noisy estimate of the cycle. We alternatively propose band-pass local polynomial regression methods aimed at isolating the cyclical component. Results are compared to standard high-pass and band-pass filters. Procedures are illustrated using the US GDP series.Econometrics2017-01-0551Article10.3390/econometrics501000112225-11462017-01-05doi: 10.3390/econometrics5010001Luis Álvarez<![CDATA[Econometrics, Vol. 5, Pages 4: Consistency of Trend Break Point Estimator with Underspecified Break Number]]>
http://www.mdpi.com/2225-1146/5/1/4
This paper discusses the consistency of trend break point estimators when the number of breaks is underspecified. The consistency of break point estimators in a simple location model with level shifts has been well documented by researchers under various settings, including extensions such as allowing a time trend in the model. Despite the consistency of break point estimators of level shifts, there are few papers on the consistency of trend shift break point estimators in the presence of an underspecified break number. The simulation study and asymptotic analysis in this paper show that the trend shift break point estimator does not converge to the true break points when the break number is underspecified. In the case of two trend shifts, the inconsistency problem worsens if the magnitudes of the breaks are similar and the breaks are either both positive or both negative. The limiting distribution for the trend break point estimator is developed and closely approximates the finite sample performance.Econometrics2017-01-0551Article10.3390/econometrics501000442225-11462017-01-05doi: 10.3390/econometrics5010004Jingjing Yang<![CDATA[IJGI, Vol. 6, Pages 6: Kinematic Precise Point Positioning Using Multi-Constellation Global Navigation Satellite System (GNSS) Observations]]>
http://www.mdpi.com/2220-9964/6/1/6
Multi-constellation global navigation satellite systems (GNSSs) are expected to enhance the capability of precise point positioning (PPP) by improving the positioning accuracy and reducing the convergence time because more satellites will be available. This paper discusses the performance of multi-constellation kinematic PPP based on a multi-constellation kinematic PPP model, Kalman filter and stochastic models. The experimental dataset was collected from the receivers on a vehicle and processed using self-developed software. A comparison of the multi-constellation kinematic PPP and real-time kinematic (RTK) results revealed that the availability, positioning accuracy and convergence performance of the multi-constellation kinematic PPP were all better than those of both global positioning system (GPS)-based PPP and dual-constellation PPP. Multi-constellation kinematic PPP can provide a positioning service with centimetre-level accuracy for dynamic users.ISPRS International Journal of Geo-Information2017-01-0561Article10.3390/ijgi601000662220-99642017-01-05doi: 10.3390/ijgi6010006Xidong YuJingxiang Gao<![CDATA[Information, Vol. 8, Pages 8: Citizen Relationship Management System Users’ Contact Channel Choices: Digital Approach or Call Approach?]]>
http://www.mdpi.com/2078-2489/8/1/8
Many municipal governments adopted 311 decades ago and have advocated access equality in citizens’ use of 311. However, the role of citizens in the development and usage of 311 remains limited. Channel choices have been discussed in various types of governmental information and communication technologies (ICTs), especially when the innovative technology has just been adopted. Much has supported the idea that 311 is viewed as a method of digital civic engagement that many municipal governments adopt to maintain citizen relationship management and the capacity for government service delivery. However, we are still unclear about how citizens use it. This study applies the theory of channel expansion to examine how San Francisco residents use the 311 system, and how citizens’ technology experiences impact their 311 digital contact channel choices rather than the 311 hotline contact channel choice. In addition, we discuss major issues in citizens’ 311 contact choices, so that 311 municipal governments may draw lessons from the San Francisco experience.Information2017-01-0581Article10.3390/info801000882078-24892017-01-05doi: 10.3390/info8010008Wei-Ning Wu<![CDATA[Informatics, Vol. 4, Pages 1: Preferences of Informal Carers on Technology Packages to Support Meal Production by People Living with Dementia, Elicited from Personalised AT and ICT Product Brochures]]>
http://www.mdpi.com/2227-9709/4/1/1
Assistive technology (AT) can help support the continued independence of people living with dementia, supported by informal carers. Opinions and preferences of informal carers towards a range of assistive and digital information and communication technologies (ICT) to support food purchase and menu selection, including navigation and online shopping, and safe meal-making by individuals living with dementia were investigated. General attitudes and experiences with assistive technologies were first probed by means of a focus group with carers (n = 6), organised through the Alzheimer’s Society in Nottingham, England. A series of AT/ICT product brochures were then produced, describing packages of technologies to enable meal production. Task-specific questions were asked of carers (n = 10) at local Memory Cafés as to the perceived capabilities of each individual for shopping and meal-making. Carers were asked to make pair-wise choices in order to select a personalised brochure and to complete a questionnaire to elicit the practicality, desirability and affordability of specific products and to probe for preferences amongst key features. Opinions on ease-of-use, aesthetics, expected safety-in-use, independence of use and stigma related to the technology packages were also collected. Results showed that carers are able to make detailed choices and express preferences about assistive and digital technologies for the individuals in their care, and customise their enabler package. Most believed that having an enabler package would improve safety. Greater exposure of carers to newer digital products would be beneficial. The brochure method could be employed on consumer websites and by AT assessors.Informatics2017-01-0541Article10.3390/informatics401000112227-97092017-01-05doi: 10.3390/informatics4010001Maria De FilippisMichael CravenTom Dening<![CDATA[MCA, Vol. 22, Pages 5: Optimal Hedging with Options and Futures against Price Risk and Background Risk]]>
http://www.mdpi.com/2297-8747/22/1/5
On the condition that both futures and options exist in the markets for hedging, this paper examines the optimal hedging strategy under price risk and background risk. Compared with the previous research, which has studied options hedging against basis risk and production risk being extended to options and futures hedging against price risk and background risk, we proposed a model and have taken the budget of buying options into consideration. The model is fairly general and some existing models are special cases of it. We firstly derive the necessary and sufficient conditions that guarantee the optimality of an under-hedge, a full-hedge and an over-hedge of futures for the risk-averse utility. Then, sufficient conditions are stipulated under which an over-hedge is optimal. Furthermore, we propose a program minimizing of tail conditional expectation (TCE), which is inherently equivalent to the risk measure of expected shortfall risk (ES) or the conditional VaR (CVaR) under the continuous-time framework. Finally, we find that ES, in our proposed model, is significantly smaller than the one in the model of options hedging only. Therefore, the results emphasize the need for combining futures hedging and options hedging, and it also shows that imposing background risk, whether it be additive or multiplicative, always has a great impact on the hedging efficiency. We also present some sensitivities of the relevant parameters to provide some suggestions for the investors.Mathematical and Computational Applications2017-01-04221Article10.3390/mca2201000552297-87472017-01-04doi: 10.3390/mca22010005Xing YuHongguo Sun<![CDATA[Algorithms, Vol. 10, Pages 5: Efficient Algorithms for the Maximum Sum Problems]]>
http://www.mdpi.com/1999-4893/10/1/5
We present efficient sequential and parallel algorithms for the maximum sum (MS) problem, which is to maximize the sum of some shape in the data array. We deal with two MS problems; the maximum subarray (MSA) problem and the maximum convex sum (MCS) problem. In the MSA problem, we find a rectangular part within the given data array that maximizes the sum in it. The MCS problem is to find a convex shape rather than a rectangular shape that maximizes the sum. Thus, MCS is a generalization of MSA. For the MSA problem, O ( n ) time parallel algorithms are already known on an ( n , n ) 2D array of processors. We improve the communication steps from 2 n − 1 to n, which is optimal. For the MCS problem, we achieve the asymptotic time bound of O ( n ) on an ( n , n ) 2D array of processors. We provide rigorous proofs for the correctness of our parallel algorithm based on Hoare logic and also provide some experimental results of our algorithm that are gathered from the Blue Gene/P super computer. Furthermore, we briefly describe how to compute the actual shape of the maximum convex sum.Algorithms2017-01-04101Article10.3390/a1001000551999-48932017-01-04doi: 10.3390/a10010005Sung BaeTong-Wook ShinnTadao Takaoka<![CDATA[Computers, Vol. 6, Pages 1: BangA: An Efficient and Flexible Generalization-Based Algorithm for Privacy Preserving Data Publication]]>
http://www.mdpi.com/2073-431X/6/1/1
Privacy-Preserving Data Publishing (PPDP) has become a critical issue for companies and organizations that would release their data. k-Anonymization was proposed as a first generalization model to guarantee against identity disclosure of individual records in a data set. Point access methods (PAMs) are not well studied for the problem of data anonymization. In this article, we propose yet another approximation algorithm for anonymization, coined BangA, that combines useful features from Point Access Methods (PAMs) and clustering. Hence, it achieves fast computation and scalability as a PAM, and very high quality thanks to its density-based clustering step. Extensive experiments show the efficiency and effectiveness of our approach. Furthermore, we provide guidelines for extending BangA to achieve a relaxed form of differential privacy which provides stronger privacy guarantees as compared to traditional privacy definitions.Computers2017-01-0461Article10.3390/computers601000112073-431X2017-01-04doi: 10.3390/computers6010001Adeel AnjumGuillaume Raschia<![CDATA[Risks, Vol. 5, Pages 2: On Comparison of Stochastic Reserving Methods with Bootstrapping]]>
http://www.mdpi.com/2227-9091/5/1/2
We consider the well-known stochastic reserve estimation methods on the basis of generalized linear models, such as the (over-dispersed) Poisson model, the gamma model and the log-normal model. For the likely variability of the claims reserve, bootstrap method is considered. In the bootstrapping framework, we discuss the choice of residuals, namely the Pearson residuals, the deviance residuals and the Anscombe residuals. In addition, several possible residual adjustments are discussed and compared in a case study. We carry out a practical implementation and comparison of methods using real-life insurance data to estimate reserves and their prediction errors. We propose to consider proper scoring rules for model validation, and the assessments will be drawn from an extensive case study.Risks2017-01-0451Article10.3390/risks501000222227-90912017-01-04doi: 10.3390/risks5010002Liivika TeeMeelis KäärikRauno Viin<![CDATA[Axioms, Vol. 6, Pages 1: Cuntz Semigroups of Compact-Type Hopf C*-Algebras]]>
http://www.mdpi.com/2075-1680/6/1/1
The classical Cuntz semigroup has an important role in the study of C*-algebras, being one of the main invariants used to classify recalcitrant C*-algebras up to isomorphism. We consider C*-algebras that have Hopf algebra structure, and find additional structure in their Cuntz semigroups. We show that in many cases, isomorphisms of Cuntz semigroups that respect this additional structure can be lifted to Hopf algebra (bi)isomorphisms, up to a possible flip of the co-product. This shows that the Cuntz semigroup provides an interesting invariant of C*-algebraic quantum groups.Axioms2017-01-0461Article10.3390/axioms601000112075-16802017-01-04doi: 10.3390/axioms6010001Dan Kučerovský<![CDATA[Electronics, Vol. 6, Pages 6: The Implementation of a High-Frequency Radio Frequency Identification System with a Battery-Free Smart Tag for Orientation Monitoring]]>
http://www.mdpi.com/2079-9292/6/1/6
Energy-harvesting passive RFID (radio frequency identification) tags provide countless possibilities as so-called smart tags. Smart tags can communicate with existing RFID readers or interrogators while providing a battery-less platform for internal and external sensors to enrich available information about the environment and smart tag it. A reduced cost and size as well as an increased lifespan and durability of battery-free smart tags offer improvements in areas such as transportation and product tracking. Battery-free smart tags can ideally support arbitrarily complex sensor measurements, but in reality energy limitations can introduce great reductions in operating range and thus application range. In this work, we present an example application of a smart tag with a passive HF (high-frequency) RFID tag IC (integrated circuit) and MEMS (micro electro-mechanical structure) sensor. A standard HF RFID reader connected to a PC (personal computer) allowed the RF (radio frequency) field to power and communicate with the smart tag. A Kalman filter, implemented on a PC, was used to correct and improve the raw sensor data of smart tag orientation. Measurement results showed that the MEMS sensor on the smart tag could be powered for continuous operation and that raw smart tag orientation data could be read while in the RF field of a standard HF RFID reader, but at a limited range.Electronics2017-01-0461Article10.3390/electronics601000662079-92922017-01-04doi: 10.3390/electronics6010006Tilen SveteNejc SuhadolnikAnton Pleteršek<![CDATA[Electronics, Vol. 6, Pages 5: Wireless Sensor Network Based Smart Grid Communications: Cyber Attacks, Intrusion Detection System and Topology Control]]>
http://www.mdpi.com/2079-9292/6/1/5
The existing power grid is going through a massive transformation. Smart grid technology is a radical approach for improvisation in prevailing power grid. Integration of electrical and communication infrastructure is inevitable for the deployment of Smart grid network. Smart grid technology is characterized by full duplex communication, automatic metering infrastructure, renewable energy integration, distribution automation and complete monitoring and control of entire power grid. Wireless sensor networks (WSNs) are small micro electrical mechanical systems that are deployed to collect and communicate the data from surroundings. WSNs can be used for monitoring and control of smart grid assets. Security of wireless sensor based communication network is a major concern for researchers and developers. The limited processing capabilities of wireless sensor networks make them more vulnerable to cyber-attacks. The countermeasures against cyber-attacks must be less complex with an ability to offer confidentiality, data readiness and integrity. The address oriented design and development approach for usual communication network requires a paradigm shift to design data oriented WSN architecture. WSN security is an inevitable part of smart grid cyber security. This paper is expected to serve as a comprehensive assessment and analysis of communication standards, cyber security issues and solutions for WSN based smart grid infrastructure.Electronics2017-01-0461Review10.3390/electronics601000552079-92922017-01-04doi: 10.3390/electronics6010005Lipi ChhayaPaawan SharmaGovind BhagwatikarAdesh Kumar<![CDATA[MTI, Vol. 1, Pages 2: Familiar and Strange: Gender, Sex, and Love in the Uncanny Valley]]>
http://www.mdpi.com/2414-4088/1/1/2
Early robotics research held that increased realism should result in increased positivity of the interactions between people and humanoid robots. However, this turned out to be true only to a certain point, and researchers now recognize that human interactions with highly realistic humanoid robots are often marked by feelings of disgust, fear, anxiety, and distrust. This phenomenon is called the Uncanny Valley. In a world in which Artificial Companions are increasingly likely, and even desired, engineering humanoid robots that avoid the Uncanny Valley is of critical importance. This paper examines theories of the uncanny, and focuses on one in particular—that humans subconsciously appraise robots as potential sexual partners. Drawing from work on love, sexuality, and gender from a variety of fields, this paper speculates on possible futures in a world of intimate companionships between humans and machines.Multimodal Technologies and Interaction2017-01-0411Review10.3390/mti101000222414-40882017-01-04doi: 10.3390/mti1010002Cheyenne Laue<![CDATA[Algorithms, Vol. 10, Pages 6: Using Force-Field Grids for Sampling Translation/Rotation of Partially Rigid Macromolecules]]>
http://www.mdpi.com/1999-4893/10/1/6
An algorithm is presented for the simulation of two partially flexible macromolecules where the interaction between the flexible parts and rigid parts is represented by energy grids associated with the rigid part of each macromolecule. The proposed algorithm avoids the transformation of the grid upon molecular movement at the expense of the significantly lesser effect of transforming the flexible part.Algorithms2017-01-04101Communication10.3390/a1001000661999-48932017-01-04doi: 10.3390/a10010006Mihaly Mezei<![CDATA[Econometrics, Vol. 5, Pages 3: Regime Switching Vine Copula Models for Global Equity and Volatility Indices]]>
http://www.mdpi.com/2225-1146/5/1/3
For nearly every major stock market there exist equity and implied volatility indices. These play important roles within finance: be it as a benchmark, a measure of general uncertainty or a way of investing or hedging. It is well known in the academic literature that correlations and higher moments between different indices tend to vary in time. However, to the best of our knowledge, no one has yet considered a global setup including both equity and implied volatility indices of various continents, and allowing for a changing dependence structure. We aim to close this gap by applying Markov-switching R-vine models to investigate the existence of different, global dependence regimes. In particular, we identify times of “normal” and “abnormal” states within a data set consisting of North-American, European and Asian indices. Our results confirm the existence of joint points in a time at which global regime switching between two different R-vine structures takes place.Econometrics2017-01-0451Article10.3390/econometrics501000332225-11462017-01-04doi: 10.3390/econometrics5010003Holger FinkYulia KlimovaClaudia CzadoJakob Stöber<![CDATA[Infrastructures, Vol. 2, Pages 1: Comparative Analysis of Triangulation Libraries for Modeling Large Point Clouds from Land and Their Infrastructures]]>
http://www.mdpi.com/2412-3811/2/1/1
Although the generation of large points clouds from geomatic techniques allows us to realize the topography and appearance of the terrain and its infrastructures (e.g., roads, bridges, buildings, etc.), all these 3D point clouds require an unavoidable step to be conveniently treated: the definition of the surface that connects these points in space through digital surface models (DSM). In addition, these point clouds sometimes have associated attributes and geometric constraints such as breaklines and/or exclusion areas, which require the implementation of efficient triangulation techniques that can cope with a high volume of information. This article aims to make a comparative analysis of different Delaunay triangulation libraries, open or with academic versions available for the scientific community, so that we can assess their suitability for the modeling of the territory and its infrastructures. The comparison was carried out from a two-fold perspective: (i) to analyze and compare the computational cost of the triangulation; (ii) to assess the geometric quality of the resulting meshes. The different techniques and libraries have been tested based on three different study cases and the corresponding large points clouds generated. The study has been useful to identify the limitations of the existing large point clouds triangulation libraries and to propose statistical variables that assess the geometric quality of the resulting DSM.Infrastructures2017-01-0321Technical Note10.3390/infrastructures201000112412-38112017-01-03doi: 10.3390/infrastructures2010001Luis Lopez-FernandezPablo Rodriguez-GonzalvezDavid Hernandez-LopezDamian Ortega-TerolDiego Gonzalez-Aguilera<![CDATA[Technologies, Vol. 5, Pages 4: Tribological Behavior of Spark Plasma Sintered Aluminum-Graphene Composites at Room and Elevated Temperatures]]>
http://www.mdpi.com/2227-7080/5/1/4
This study examines the role of Graphene nanoplatelets (GNPs) as a solid lubricant additive to aluminum. Pure Al and Al-2 vol % GNP pellets are sintered by Spark Plasma Sintering (SPS). Their tribological properties are evaluated by a ball-on-disk tribometer at room temperature (RT) and high temperature (200 °C). Al-2 vol % GNP composite displayed poor densification (91%) and low hardness, resulting in poor wear resistance as compared to pure Al. However GNP addition resulted in a lower coefficient of friction (COF) as compared to pure aluminum at both temperatures. The results demonstrated that GNPs contribute to reducing COF by forming a protective tribolayer. GNPs also play a unique role in reducing oxygen ingress at 200 °C. It is concluded that the packing density of a starting powder blend of Al-GNP needs to be improved by using irregular shaped aluminum powder mixed with both larger and smaller GNPs. This would result in greater densification and improve wear rate while maintaining low COF.Technologies2017-01-0351Article10.3390/technologies501000442227-70802017-01-03doi: 10.3390/technologies5010004Sara RengifoCheng ZhangSandip HarimkarBenjamin BoeslArvind Agarwal<![CDATA[Information, Vol. 8, Pages 7: Model Based Safety Analysis with smartIflow †]]>
http://www.mdpi.com/2078-2489/8/1/7
Verification of safety requirements is one important task during the development of safety critical systems. The increasing complexity of systems makes manual analysis almost impossible. This paper introduces a new methodology for formal verification of technical systems with smartIflow (State Machines for Automation of Reliability-related Tasks using Information FLOWs). smartIflow is a new modeling language that has been especially designed for the purpose of automating the safety analysis process in early product life cycle stages. It builds up on experience with existing approaches. As is common practice in current approaches, components are modeled as finite state machines. However, new concepts are introduced to describe component interactions. Events play a major role for internal interactions between components as well as for external (user) interactions. Our approach to the verification of formally specified safety requirements is a two-step method. First, an exhaustive simulation creates knowledge about a great variety of possible behaviors of the system, especially including reactions on suddenly occurring (possibly intermittent) faults. In the second step, safety requirements specified in CTL (Computation Tree Logic) are verified using model checking techniques, and counterexamples are generated if these are not satisfied. The practical applicability of this approach is demonstrated based on a Java implementation using a simple Two-Tank-Pump-Consumer system.Information2017-01-0381Article10.3390/info801000772078-24892017-01-03doi: 10.3390/info8010007Philipp HönigRüdiger LundeFlorian Holzapfel<![CDATA[JRFM, Vol. 10, Pages 1: Portfolio Optimization and Mortgage Choice]]>
http://www.mdpi.com/1911-8074/10/1/1
This paper studies the optimal mortgage choice of an investor in a simple bond market with a stochastic interest rate and access to term life insurance. The study is based on advances in stochastic control theory, which provides analytical solutions to portfolio problems with a stochastic interest rate. We derive the optimal portfolio of a mortgagor in a simple framework and formulate stylized versions of mortgage products offered in the market today. This allows us to analyze the optimal investment strategy in terms of optimal mortgage choice. We conclude that certain extreme investors optimally choose either a traditional fixed rate mortgage or an adjustable rate mortgage, while investors with moderate risk aversion and income prefer a mix of the two. By matching specific investor characteristics to existing mortgage products, our study provides a better understanding of the complex and yet restricted mortgage choice faced by many household investors. In addition, the simple analytical framework enables a detailed analysis of how changes to market, income and preference parameters affect the optimal mortgage choice.Journal of Risk and Financial Management2017-01-03101Article10.3390/jrfm1001000111911-80742017-01-03doi: 10.3390/jrfm10010001Maj-Britt NordfangMogens Steffensen<![CDATA[Symmetry, Vol. 9, Pages 6: Some Computational Aspects of Boron Triangular Nanotubes]]>
http://www.mdpi.com/2073-8994/9/1/6
The recent discovery of boron triangular nanotubes competes with carbon in many respects. The closed form of M‐polynomial of nanotubes produces closed forms of many degree‐based topological indices which are numerical parameters of the structure and, in combination, determine properties of the concerned nanotubes. In this report, we give M‐polynomials of boron triangular nanotubes and recover many important topological degree‐based indices of these nanotubes. We also plot surfaces associated with these nanotubes that show the dependence of each topological index on the parameters of the structure.Symmetry2017-01-0191Article10.3390/sym901000662073-89942017-01-01doi: 10.3390/sym9010006Mobeen MunirWaqas NazeerShazia RafiqueAbdul NizamiShin Kang